User:LightandDark2000/January 1862 North American Megastorm

January 1862 North American Megastorm

Extratropical cyclone (SSHWS)
A similar Aleutian Low strengthening in the Gulf of Alaska.
Type	Aleutian Low Extratropical cyclone
Formed	October 27, 1861
Dissipated	February 16, 1862
Highest winds	1-minute sustained: 160 mph (260 km/h)
Lowest pressure	940 mb (27.76 inHg)
Fatalities	>10,000 total
Damage	≥$100 million (1861 USD); ≥$299.9 billion (2021 USD)
Areas affected	Russia, Japan, Canada, Alaska, United States, Northern Mexico, Southern Greenland, Europe
Part of the 1861–62 North American winter

The January 1862 North American Megastorm, also known as the 1861–62 ARkStorm, was the most destructive extratropical cyclone to impact the region of Oregon, Nevada, California, and other Western States, in recorded history, since meteorological records began, occurring from November 1861 to January 1862. The storm was also ranked a Category 5 Extreme Winter storm on the NESIS Scale. The system was preceded by weeks of continuous rain (or snow in the high elevations) that began in Oregon in November 1861 and continued into January 1862. This was followed by record quantitative precipitation in January 9–12, which contributed to a flood that extended from the Columbia River in western Oregon southward through California to San Diego, and extended as far inland as Idaho in the Washington Territory, Nevada and Utah in the Utah Territory, and Arizona in the western New Mexico Territory.

The storm was climaxed by a warmer, intense storm with a lot of rain that was made more serious by the earlier large accumulation of snow, now melted by the rain in the lower elevations of the mountains. Throughout the affected area, all of the streams and rivers rose to great heights, flooded the valleys, inundated or swept away towns, mills, dams, flumes, houses, fences, and domestic animals, and ruined fields. Early estimates of property damage was at $10,000,000 (1861 USD).^[1] However, later it was estimated that approximately one-quarter of the taxable real estate in the state of California was destroyed in the flood. Dependent on property taxes, the State of California went bankrupt. The Megastorm caused approximately $100 million 1861 USD in damage, approximately equal to $299.9 billion (2021 USD). The governor, state legislature, and state employees were not paid for a year and a half.^[2] At least 4,000 people were estimated to have been killed in the floods in California, which was roughly 1% of the state population at the time.^[3] 200,000 cattle drowned, and the state's economy shifted from ranching to farming.^[4]

Meteorological history

Preparations

Little to no preparations were made in advance of this storm, as Meteorology was not as advanced back then as it is today. Thus, most people in the Western United States were caught off guard by this storm's ferocity and impacts.

Impacts

Background

The floods were likely caused by precipitation from atmospheric rivers, or narrow bands of water vapor about a mile above sea level that extend for thousands of kilometers.^[5]

The floods followed a 20-year-long drought.^[6] Prior to the flooding, Oregon had steady but above-average rainfall during November, as well as heavier snow in the mountains.^[7]

The weather pattern that caused this flood was not an El Nino, but from the existing Army and private weather records, it has been determined that the polar jet stream was to the north as the Pacific Northwest experienced a mild rainy pattern for the first half of December 1861. Then, the jet stream slid south and freezing conditions were reported at Oregon stations by December 25. Heavy rainfall began falling in California as the longwave trough moved down over the state, remaining there until the end of January 1862 and causing rain to fall everywhere in the state for nearly 43 days. Eventually, the trough moved even further south, causing snow to fall in the Central Valley and surrounding mountain ranges.^[8]

Canada

Canada experienced large waves, powerful winds, large amounts of snow, and heavy precipitation, as the Megastorm stalled in the Gulf of Alaska, for almost a month. The Megastorm returned to impact Atlantic Canada, when the storm was exiting the Eastern United States.

United States

Washington

As the Megastorm began to impact the West Coast of the United States, the state of Washington experienced extremely high wind, massive downpours and flooding, along with a large storm surge measuring 50 feet high. The state also experience beach erosion, due to the onslaught of the storm.

Oregon

There was an excess of precipitation in November 1861 over most of Oregon, less so in the extreme northwest. It was cold enough at the higher elevations so that much snow fell in the Cascade Mountains, which when later melted by the warm rains produced the great quantity of water which flooded into the Willamette River and other streams in the Cascades. Tributaries of the Willamette rising in the Oregon Coast Range did not rise so high. Then the depression that came in at the beginning of December, produced strong, warm southerly winds in Oregon, with extremely heavy rain. The crest of the flood was reached at Salem on December 3rd, at Oregon City on the 4th, and at Milwaukie, between Oregon City and Portland, on the 5th, at Albany December 8th, a second rise at Albany greater than the first. The crest at Albany and Salem were the highest ever known at any time. In Oregon, the flood was one of the largest in the history of the Willamette Valley and the rest of Western Oregon. Flooding was heaviest on rivers with tributaries arising from the snow covered Cascade Mountains. ^[7]

An article in the December 14, 1861, Oregon City Argus, described the course of the flood at Oregon City:

During the month of November the rain had been falling almost continuously, and a vast amount of snow must have accumulated in the mountains. No snow, however, had fallen in the Willamette Valley, and the river, up to Sunday, December 1st, exhibited no indication of an unusual rise. It might have been noticed, and doubtless will be again if the phenomenon ever occurs hereafter, that November's long and rather cold rain was succeeded during the closing days of the month by a warm, humid state of the air, rain falling in copious showers almost without intermission. On Sunday the river looked swollen and threatening, but, until still later, no serious apprehensions were entertained. On Monday morning the steamer Rival left this place for Portland while the Express came up on her usual trip, but finding navigation difficult and dangerous they concluded to leave the trip half done, each boat stopping at the wrong end of her route. The Onward also started up the river on her usual trip. The Island Mill was kept running Monday and through the night. Mr. John Chapman and his wife were on the Island at the time, and unaware of danger. But the crash of the falling bridge just before daylight, destroying all egress to the main land, roused them to a consciousness of immediate danger, and they passed several anxious hours before help could be extended to them and they could be extricated from their perilous situation in skiffs from below. This was accomplished safely and in good time, for the water was rising rapidly, and by afternoon rushed down the chasm over which the bridge had stood in a way to prevent all approach. This afternoon (Tuesday) a large part of the breakwater at the warehouse on the opposite side of the river succumbed to the immense pressure of water, and at intervals great masses of timbers comprising the crib-work would burst up and be swept away by the mighty torrent.

Tuesday evening a gloom settled on a scene such as probably never was witnessed in our Valley before. The ceaseless roar of the stream made a fearful elemental music widely different from the ordinary monotone of the Falls; while the darkness was only made more visible by the glare of torches and hurrying lights, which with the shouts of people from the windows of houses surrounded by the water, all conspired to render the hour one of intense and painful excitement. The flood has covered the highest mark of January '53, and is still rapidly rising. As late as anything could be seen the mills were still standing, but the insatiate monster is still creeping up inch by inch, winding its swelling folds round the pillars and foundations of all the houses in its way, crushing and grinding them in the maw of destruction, and sweeping the broken fragments into a common vortex of ruin. All night as on the night previous, people whose homes were being invaded hurried to places of security, glad to escape even with the sacrifice of all their goods.

The light of Wednesday morning revealed a scene of desolation terrible in its extent no less than in its completeness. The Oregon City and Island Mills, Willamette Iron Works, Foundry and Machine Shop; all the breakwaters designed to protect the mills and upper end of Oregon City except one short piece are carried away, and over where they stood now sweeps a foaming current against which no building unprotected by a solid breakwater as a defense could possibly stand. An immense amount of drift has passed and apparently the debris of many houses but everything is ground so fine and is hurried out of sight so quickly that little can be known for certain. On the fragments of a large barn, as appeared by the quantity of grain, straw, etc., sat a number of chickens, bearing melancholy evidence of devastation above. We were compelled to vacate our office this afternoon, the water rising nearly two feet on the floor. Main Street is navigable for skiffs past our door down as far as the Masonic Hall. ^[7]

Flood waters were so high that at Oregon City at the floods crest on December 5th, the steamer St. Clair was able to run the falls and steamers were able to visit points at some distance from the normal river channel. Although large amounts of wheat and flour were swept away, some was recovered when Oregon City's Island Mill was found on Sauvie Island downriver from Portland. The nearby town of Linn City was completely destroyed by flooding and was not rebuilt.^[9] In addition, the flood destroyed the historic town of Champoeg, site of the first provisional government in Oregon, and Orleans, Oregon, across the Willamette River from Corvallis. Neither were rebuilt.^[7]

In other parts of Oregon flooding was severe also. The Umpqua River had the greatest flood known even to the oldest Indians, and water was 10 to 15 feet higher than the 1853 flood. It rose from November 3rd to December 3rd, subsided for two days then rose again until the 9th. At Fort Umpqua, communication up river was cut off above Scottsburg, and the river was full of floating houses, barns, rails and produce. At Port Orford, the Coquille River swept away settlers' property and also did great damage on the Rogue River and on other small streams."^[7]

Flood damage was so great because the rivers in Oregon were the main routes of travel. The river front was the building site of mills, freight depots, and storehouses for grain and other foodstuffs. Business houses and many residences were near the landings. Farm buildings were mostly on sites convenient to the rivers, along with supplies of feed for livestock. Loss of so much wheat flour and demand from the new Idaho gold fields caused a spike in its price from $7 to $12 per barrel.

Northern California

Fort Ter-Waw, located in Klamath, California, was destroyed by the flood in December 1861 and abandoned on June 10, 1862.^[10] Bridges were washed away in Trinity and Shasta Counties.^[11] At Weaverville, John Carr was a witness to the sudden melt of snow by the heavy rain and onset of the flood in December 1861 on the Trinity River:

The winter of 1861–2 was a hard one. From November until the latter part of March there was a succession of storms and floods. I remember my being in Weaverville; I think it was in the month of December, 1861. ... It had been raining all the day previous. The ground was covered with snow one foot deep, and on the mountains much deeper. We arrived at the ranch just before dark, and I wanted to cross his bridge and stay at John Carter's that night, but “Uncle” Strudivant would not listen to any such thing. Stay with him I must. He told me that the bridge was named Jeff Davis, and that old Trinity could not carry enough water to wash "Jeff" out,.... He had a private cottage a short distance from the ranch and toll-house. It was close to the foot of the mountain, the divide between Weaverville and the Trinity River. ... He and I advocated our respective sides of the political issues until 11 o'clock, when we "turned in." It rained all afternoon and night. The weather had turned warm, and the rain came down in torrents. Several times I went to the door during our political discussion, and every time it seemed to be raining harder, and I wished myself on the otherside of Trinity River. I frequently said, "Uncle Joe, I am afraid the bridge will go." His reply was, "Jeff will stand it." ... We slept until about 4 o'clock in the morning, when Jerry Whitmore, one of Uncle Joe's partners, came to where we were, and knocked on the door to wake us up. Uncle Joe called out, "What is wanted?" Jerry replied. "The bridge is gone—not a stick left, and, the water will soon be up to the house."

The water in the river had been rising all night, and men were stationed on the bridge with poles to keep logs from striking the piers. At about 4 o'clock in the morning a large spruce tree came down the river with roots, branches and all. The men seeing it come, and knowing the bridge was doomed, escaped from the bridge before the roots of the tree struck it. It was well they did, for one of the men who were on the bridge told me next morning that as soon as the tree struck the bridge it went through it as if nothing had been in its way, cutting it completely in two, and the whole structure fell into the river and was soon out of sight. As soon as daylight came Uncle Joe and I went to the ruins. Not a plank of the bridge was left. The rain was yet pouring down. The snow was nearly all gone. Everything around the place looked desolate. On the flat where the house was built they had the finest bearing orchard in Northern California. If the river rose but a little more, the trees would be swept away, and the house with them. All the forenoon the river continued to rise, and at last it began to spread over the orchard and wash the black loam away. Finally, as the current became stronger amongst the trees, one after another began to fall, some floating off with the water, and others hanging by the roots. Trinity that morning was playing havoc with the settlers on its banks. It was dreadful to look upon. Standing on high ground, one could see property of all kinds on its way to the ocean. The river itself seemed like some mighty uncontrollable monster of destruction broken away from its bonds, rushing uncontrollably on, and everywhere carrying ruin and destruction in its course. When rising, the river seemed highest in the middle. When falling, it became lowest in the middle, and all the drift worked toward the center of the stream. When the river was at or near its highest, one could see floating down parts of mills, sluice-boxes, miners cabins, water-wheels, hen-coops, parts of bridges, bales of hay, household furniture, sawed lumber, old logs, huge spruce and pine trees that had withstood former storms for hundreds of years—all rushing down that mad stream on their way to the boundless ocean. From the head settlement to the mouth of the Trinity River, for a distance of one hundred and fifty miles, everything was swept to destruction. Not a bridge was left, or a mining-wheel or a sluce-box. Parts of ranches and miners cabins met the same fate. The labor of hundreds of men, and their savings of years, invested in bridges, mines and ranches, were all swept away. In forty-eight hours the valley of the Trinity was left desolate. The county never recovered from that disastrous flood. Many of the mining-wheels and bridges were never rebuilt.^[12]

Flooding of the Central Valley

"The rainy season commenced on the 8th of November, and for four weeks, with scarcely any intermission, the rain continued to fall very gently in San Francisco, but in heavy showers in the interior. According to the statement of a Grass Valley paper, nine inches of rain fell there in thirty-six hours on the 7th and 8th inst. Whether, it is possible that so much rain could fall in thirty-six hours I will not decide; but it is certain that, the amount was great, for the next day the river-beds were full almost to the hilltops. The North Fork of the American River at Auburn rose thirty-five feet, and in many other mountain streams the rise was almost as great. On the 9th the flood reached the low land of the Sacramento Valley." ^[7]

Like many other towns along the tributary rivers to the Sacramento and San Joaquin Rivers, at Knight's Ferry, its homes, its mill and most of its businesses were ruined by the flood. Its bridge spanning the Stanislaus River withstood the flood waters but was destroyed when the debris of the bridge at Two-Mile Bar, only a short distance up river, torn from its foundation, crashed into the Knights Ferry Bridge, crushing the truss supports and knocking it from its rock foundation.^[13] Some towns like Empire City and Mokelumne City were destroyed entirely.

The entire Sacramento and San Joaquin valleys were inundated for an extent of 300 miles (480 km), averaging 20 miles (32 km) in breadth.^[14] John Carr wrote of his riverboat trip up the Sacramento River when it was at one of its highest stages of flood:

… I was a passenger on the old steamer "Gem", from Sacramento to Red Bluff. The only way the pilot could tell where the channel of the river was, was by the cottonwood trees on each side of the river. The boat had to stop several times and take men out of the tops of trees and off the roofs of houses. In our trip up the river we met property of every description floating down—dead horses and cattle, sheep, hogs, houses, haystacks, household furniture, and everything imaginable was on its way for the ocean. Arriving at Red Bluff, there was water everywhere as far as the eye could reach, and what few bridges there had been in the country were all swept away. I managed to get to Cottonwood, and had to lay over for a week before any of the streams between there and Hay Fork Valley were fordable. ^[7]

The city of Sacramento suffered the worst damage due to its levee, which lay in a wide and flat valley at the junction of the American and Sacramento Rivers. When the floodwaters entered from the higher ground on the East, the levee acted as a dam to keep the water in the city rather than let it flow out. Soon the water level was 10 feet higher inside than the level of the Sacramento River on the outside. Dozens of wood houses, some two stories high, were simply lifted up and carried off by the flood, as was "all the firewood, most of the fences and sheds, all the poultry, cats, rats and many of the cows and horses". A chain gang was sent to break open the levee, which, when it finally broke, allowed the waters to rush out of the city center and lowered the level of the flooding by five to six feet. Eventually the waters fell to a level on a par with the lowest part of the city.^[7]

Southern California

In Southern California, beginning on December 24, 1861, it rained for almost four weeks straight, resulting in a total of 35 inches of rain in Los Angeles. The flooding drowned thousands of cattle and washed away fruit trees and vineyards that grew along the Los Angeles River. No mail was received at Los Angeles for five weeks. The Los Angeles Star reported that:

The road from Tejon, we hear, has been almost washed away. The San Fernando mountain cannot be crossed except by the old trail ... over the top of the mountain. The plain has been cut up into gulches and arroyos, and streams are rushing down every declivity. ^[15]

The plains of Los Angeles County, at the time a marshy area with many small lakes and several meandering streams from the mountains, were extensively flooded, and much of the agricultural development which lay along the rivers was ruined. In most of the lower areas small settlements were submerged. These flooded areas formed into a large lake system with many small streams and a few more powerful currents cut channels across the plain and carried the runoff to the sea.

At Santa Barbara County the narrow coastal plains were flooded by the rivers coming out of the mountains, and the town of Ventura was abandoned.

In San Bernardino County, all the fertile riverside fields and all but the church and one house of the New Mexican colony of Agua Mansa, were swept away by the Santa Ana River, which overflowed its banks. The ringing church bell on the night of January 22, 1862 alerted the inhabitants to the approach of the flood, and all escaped.^[16]

Downriver in Los Angeles County, (including what is now Orange County) the flooding Santa Ana River created an inland sea lasting about three weeks with water standing 4 feet (1.2 m) deep up to 4 miles (6 km) from the river.^[14] In February 1862, the Los Angeles, San Gabriel, and Santa Ana Rivers merged. Government surveys at the time indicated that a solid expanse of water covered the area from Signal Hill to Huntington Beach, a distance of approximately eighteen miles.

In San Diego a storm at sea, backed up the flood water running into the bay from the San Diego River, resulting in a new river channel cut into San Diego Harbor. The continuous heavy downpour also changed the look of the land; the previously rounded hills were extensively cut by gullies and canyons.^[17]

To the north, in the Owens Valley, similar snow and flooding conditions as those to the east in Aurora, lead to the local Paiute suffering the loss of much of the game they depended on. Cattle newly driven into the valley to feed the miners competed with the native grazers, and ate the native wild plant crops the Paiute depended on to survive. Starving the Paiute began to kill the cattle, and conflict with the cattlemen began, leading to the subsequent Owens Valley Indian War.

Arizona

In western New Mexico Territory, heavy rains fell in late January causing severe flooding of the Colorado and Gila Rivers. On January 20, 1862 the Colorado River began to rise, and on the afternoon of January 22, it rose suddenly in three hours from an already high stage nearly six feet, overflowing its banks and turned Fort Yuma into an island in the midst of the Colorado River. At 1 o’clock on the morning of January 23, the river reached its crest.^[18] Colorado City, across the Colorado River from Fort Yuma, was washed away. The river overflowed its banks to the extent that there was water twenty feet deep on a ranch in the low lying ground just above the town where the Gila River joined the Colorado. The riverside home of steamboat entrepreneur George Alonzo Johnson and the nearby Hooper residence were the only places in the town unharmed because they were built on high ground.^[19] Colorado City had to be rebuilt on higher ground after the 1862 flood.^[20]

The Gila River also flooded, covering its whole valley at its mouth where it met the Colorado from the sand hills on the south to the foothills on the north. Twenty miles to the east of Fort Yuma, it swept away most of the mining boomtown of Gila City along with a supply of hay being gathered there to supply the planned advance of the California Column into Confederate Arizona. Further east the road was flooded, buildings and vehicles swept away and traffic was disrupted for some time thereafter by the mud covering the road to Tucson.^[21] The great flood in the Gila and Colorado Rivers, covered their bottom lands with mud. Much of the livestock along the rivers drowned and the crops of the Indians along the river were destroyed.^[22]

The overflow of the 1862 Colorado River flood waters reached the Salton Sink via the Alamo and New River filling it creating a lake some 60 miles long and 30 miles wide.^[23]

Nevada

The Carson River Basin of Eastern California, and the Western Utah Territory (which is now now Nevada), also suffered from a similar pattern of flooding. Flooding began in December, 1861 in Carson Valley from a series of storms in the upper Carson River basin. Two feet of wet heavy snow fell on December 20, 1861, accumulating on the valley floor. Snow was followed by a period of very cold temperatures which froze the snow, followed by a three day rain starting on December 25, 1861. By January 2, 1862, the town of Dayton and the area surrounding it had been flooded.^[24]

In the vicinity of Aurora there had been light snowfall in November, then mild weather until Christmas Eve when it began a heavy and rapid snowfall for days, the temperature dropped below zero and the passes over the Sierras were closed. During the second week of January it warmed slightly and the snow became a torrential rain. Esmerelda and Willow gulches overflowing their banks flooded Aurora, with water standing up to three inches deep in many buildings, adobe buildings turned to mud and collapsed. After a week it cooled again and snow began to fall again. Within a few days the snow was deeper than it had been before the rains had begun to fall. Samuel Young of Aurora, recorded in his diary that the snow and rain had fallen for twenty six days out of thirty since December 24, 1861.^[25]

Utah

The early southwestern Utah settlements in Washington County, St. George, Grafton, Duncans Retreat, Adventure, and Northrop, Utah were nearly destroyed by a flood that followed forty-four days of rainfall in January and February 1862.^[26] Springdale, and Rockville were founded in 1862 by settlers flooded out of Adventure, Northup and other places in the vicinity.

Idaho

In the interior of Washington Territory the storm creating the flood in Oregon dumped its precipitation as an unprecedented snowfall. Flooding on the Columbia River and the snow in the mountains, closed off supplies to the new mining towns on the Salmon River, causing starvation among the miners of Florence, cutoff from December until May 1862. In early July, as the heavy burden of snow in the Mountains melted, the runoff caused great flooding. The Boise River flooded from extremely high runoff and is believed to been four times larger than its largest recorded flood in 1943. Flood waters made the river expand to a couple of miles wide.^[27] It washed away or covered the original route of the Oregon Trail in the river valley.^[28]

Eastern United States

The Eastern part of the United States experienced the Mega Storm as an exceptionally powerful Blizzard, which spawned a large amount of Tornadoes (as the system was strengthened by moisture from the Gulf of Mexico), caused heavy flooding, record amounts of snow, and extremely windy conditions. The gales reached hurricane-strength periodically.

Mexico

Northern Mexico suffered damage from the storm, as it passed through the Southwestern United States.

Greenland

As the Megastorm passed to the south of Greenland, Southern Greenland experienced fierce winds, and large amounts of snowfall.

Europe

The Megastorm caused widespread flooding, massive amounts of snow, and wind damage in Europe, before moving on to Western Russia. Several tornado outbreakes also resulted from this storm.

Mediterranean Region

The islands in the Mediterranean Sea suffered from severe flooding, powerful tropical storm-force winds, and from the powerful thunderstorms.

North Africa

The storm did not have much of an impact in North Africa, but it still brought powerful winds and moderate flooding.

Russia

When the Megastorm left Eastern Russia as a weak Extratropical system, shortly after it had formed, the storm did little to no damage there. However, when the storm returned to Western Russia, it brought large amounts of snowfall, and tropical storm force winds, before dissipating in the extreme Northeastern Russia. During the duration of the storm, it caused blizzard conditions, and an unknown amount of damage.

Aftermath

In the wake of the Megastorm, huge portions of California were left submerged, including most of Central Valley, which had then become a temporary sea. The extratropical cyclone cut a path of destruction wherever it went, resulting in about $100 million US dollars (2011) of damage. Because about 1/4 of California's taxable real estate land was destroyed in the flood, the state went bankrupt. It would take many years for California alone to recover from the damage.

Records

This storm broke the record of being the most powerful non-tropical storm to impact the West Coast of North America, since reliable records began. Huge portions of California, including Central Valley, became temporary seas. For the first time in recorded history, this storm had resulted in heavy rain non-stop in California for 45 days in a row, allowing 10 feet of rain to be dumped.

History of the North American Megastorms

The USGS sediment research in the San Francisco Bay Area, Santa Barbara basin, Sacramento Valley, and Klamath Mountains region have indicated that Megastorms have occurred in the following years A.D.: 212, 440, 603, 1029, c. 1300, 1418, 1605, 1750, 1810, and December 1861–January 1862 (the latest Megastorm occurrence). Based on the intervals of occurrences, scientists have discovered that Megastorms have occurred every 50 to 430 years, with a mean return period of around 150–200 years.^[29] That means that as of October 2018, another Megastorm probably won't impact North America for another 3 to 281 years (from 2021 to 2292). But scientists have noted that the 1605 storm was the most powerful one in the group, with an interval of 185 years. This shows that the longer North America is overdue for a Megastorm, the more likely the storm will occur within the next several years from then, and the more powerful it could potentially be.

Intensity of the Megastorms

Geologic evidence indicates that at least several of the previous Megastorms were larger and more severe in magnitude than the most recent episode, particularly the events in 440, 1418, 1605, and 1750, each of which left behind silt layers more than an inch think in the Santa Barbara basin or the San Francisco Bay Area. The most powerful ARkStorm was the 1605 event, which left behind the thickest layer of silt, at 2 inches; data indicates that this event was at least 50% larger than any of the other ARkStorms. The events larger than the 1861–62 Megastorm seem to occur every 200 years or so, indicating that ARkStorms that occur after longer intervals may end up being more powerful.^[29]

Notability

Scientists have discovered that this Megastorm did not take place during an El Niño year, according to the research done at the University of Oregon, by climatologists Victor Neal and William Quin. Their analysis indicates that a polar jet that swept down to central California in December and then fluctuated north and south over the Northwest and California for two months interacting with a persistent Aleutian Low (this Megastorm) that bowled one storm after another into California, before eventually coming down to impact California itself, in mid-January 1862. However, one must assume, given the prodigious rainfall amounts, that a massive subtropical stream of moisture, or atmospheric river, must have fed into this system.^[30]

Future Megastorm Impacts

Meteorologists have determined that if a Megastorm of the same intensity struck the Western United States today, the damage done would cost about $750 billion dollars (2011 USD). Millions of people would be forced to evacuate, and hundreds of thousands would be left homeless. Huge portions of California would be flooded once again, and the U.S. economy would suffer immensely from the damage.

See also

References

External links

• ArKStorm: California's Other "Big One" - University of California, Berkeley
• Null, J.; Hulbert, J. (2007). "California Washed Away: The Great Flood of 1862". Weatherwise. 60 (1): 26–30. doi:10.3200/wewi.60.1.26-30.
• Eric Zerkel (December 21, 2017). "California: The Flood That Could Change Everything". The Weather Company. Retrieved December 24, 2017.

Category:California
Category:1861 natural disasters
Category:1862 natural disasters
Category:Natural disasters in California
Category:Natural disasters in Idaho
Category:Natural disasters in Nevada
Category:Natural disasters in Oregon
Category:Natural disasters in Utah
Category:History of California