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Alaska Statewide Summary
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| April 2012 | | ||||||||||||||||||||||
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Spring proceeded to develop gradually over Alaska as April progressed. There was no sudden change in a pattern of weak circulation that held for most of the month. The series of months with above normal temperatures alternating with months with below normal temperatures continued. However, April's temperatures departed much less from normal that those of November through March. Overall, April was a mild month in several respects. For the most part, precipitation in April was below normal, with the exception of the Interior near the Yukon border, where amounts were up to twice the normal values. Precipitation was much below normal over the north end of Southeast Alaska and especially in the Interior from Fairbanks to Galena, where amounts were just 10 percent of normal. On April 7, the winter snowfall at Anchorage reached a total of 133.6 inches – one inch over the previous record set in the winter of 1954-1955. Snowfall records at Anchorage go back 63 years. The heavy snow cover in south central Alaska and along the north gulf coast and Prince William Sound was steadily settling and melting away all month. Although residents expected the huge volume snowmelt and runoff that was certain to occur to bring serious flooding, it did not happen. The slow and steady pace of runoff resulted in much fewer problems with high water that a large and sudden warming, which would very likely have caused serious flooding. The Arctic portion of Alaska – north of the crest of the Brooks Range – began the month with subzero temperatures, but by April 10, above zero weather was the rule. By then, winter was definitely ending. The last real taste of winter was a blizzard in Atigun Pass, where the Dalton Highway crosses the Brooks Range, on April 30. High pressure held over the Chukchi and Beaufort Seas, as it often does in April. There was very little stormy weather there during April. Clear weather was abundant over the Interior and south central Alaska during April. High country and downhill skiing conditions continued to be excellent. The snow at the base of the Eaglecrest ski resort near Juneau was over 100 inches for almost half of April. The Alaska Mountain Wilderness Ski Classic, held on a 200 mile course running through the Brooks Range, and the Arctic Man Ski and Sno-Go Classic Race in the Hoo Doo Mountains of the central Alaska Range were held under ideal blue skies and temperatures from 15 below to 20 above which are typical of late winter in mainland Alaska. The large amount of snowmelt in south central Alaska refroze as it flowed down some steep, rocky slopes. This process is not unusual, though the amount of ice was large. Normally such ice accumulations shed small chunks over time. On April 6, a large ice slide occurred on steep rock slopes above the Seward Highway, south of Anchorage. In this case, a huge ice block was released all at once. The ice crushed a vehicle that was driving on the road below, trapping the driver. A quick-thinking tow truck driver used his vehicle's boom to pull up the roof on the car, enabling the woman inside to resume breathing...and to survive. Warm weather developed in much of mainland Alaska at mid April, and a number of new calendar day high temperature records were established. The melting of the heavy snow pack on steep mountain slopes near Cordova resulted in a large snow and mudslide on April 17. A 300 foot section of the road between the town and the airport was covered with snow and mud 20 to 40 feet deep. There were no injuries, nor any damage. A crew of five loader operators cleared the debris and had the road open in a few hours. By mid April, the snow on main roads in Anchorage had melted and the pavement was dry. Sand and dust particles spread on the road surfaces during the winter were quickly lofted by afternoon breezes. The dust particle concentrations around Anchorage rose to levels between good and unhealthy from the 3rd through the 19th. Though roads around communities on the southern mainland of Alaska were clear by mid April, outdoor tracks and athletic fields still had snow and plenty of mud. Some track events were cancelled. Some events were moved inside gymnasiums or to parking lots. One local reporter observed that spring may be in the air, but winter was still on the ground. The annual Spring migration of birds into Alaska proceeded right on schedule. The first flock of geese of the season arrived in Fairbanks on April 9, and the influx of much greater numbers and different species then increased as usual. By the end of April, the songs of the birds were floating over the woods and fields of much of mainland Alaska. As spring advanced, Alaskan rivers started coming to life. As they do every year, small streams and tributaries were the first to open. At the beginning of April, the ice on Interior rivers at established measuring sites ranged from 21 inches to 51 inches thick. The ice on the Colville River, in the Arctic west of Prudhoe Bay, was 72 inches thick. Ice jams formed on the Tanana River upstream from Fairbanks on April 20. Minor flooding ensued for five days in the Salcha area. Some homes had to be reached by canoe. Downstream at Nenana, the Tanana River went out on the evening of April 23 – its 4th earliest breakup in 96 years of records. Further down the Tanana River, an ice jam formed downstream from Manley Hot Springs on April 27. Water was backed up six miles and most of the town was flooded. The water levels there were the highest in 30 years. The ice jam broke and the flooding ended on the night of April 29-30. After being snow-free for over a week, lower elevation land was drying, especially in the central Interior. Several small grass fires sprang up during the last 10 days of April. |
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The ocean weather around Alaska was gentler than it had been in almost a year. Gale force winds blew somewhere over Alaskan waters on 18 days of April. The strongest storm of April appeared as a developing low pressure system which moved northward, crossing the central Aleutians on the afternoon of April 7, and reaching the central Bering Sea as a 976 millibar (28.82 inches) low on the afternoon of April 8. The low weakened about 200 miles west of Saint Lawrence Island on the night of April 8-9. Southeasterly gales blew over the eastern Bering Sea and all of the adjacent Alaska coastal regions all day on April 8. On the northern perimeter of this storm, blizzards occurred on the night of April 7-8 at Wales, on Bering Strait and at Savoonga, on Saint Lawrence Island. Winds and seas in the Gulf of Alaska were generally lighter than normal, and a number of boats reported frequently pleasant, sunny days. The halibut fishery was quite successful, and free of serious mishaps. As April began, cool north winds held the edge of the Bering Sea pack ice as far advanced as at any time of the winter. All of Bristol Bay and the Pribilof Island waters were ice-covered. The ice began to withdraw a little during the last week of April. There was considerably more ice cover than at the same time a year before. On April 2, the north half of Cook Inlet and part of Kamishak bay were was ice covered. By April 20 the Inlet was ice free. This was about two days earlier than in the year before. In the first week of April, sea surface temperatures in Alaskan waters were from 2°F to 4°F cooler than normal, except near the ice edge in the Bering Sea, where surface waters were from 4°F to 8°F colder than normal. By the end of April, sea surface temperatures on the north coast of the Gulf of Alaska were up to 1°F above normal. The Cleveland Volcano, located in the eastern Aleutians, had small eruptions on April 4 and April 20. Otherwise, Alaskan volcanoes were quiet. A 5.4 magnitude earthquake occurred on April 11 near Adak Island, in the central Aleutians. The quake was felt in Adak, but did no damage. |
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Click on the graphic for an expanded view. For a high resolution image, please contact us.
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| Posted: May 12, 2012 Summary information is compiled and produced monthly by the Fairbanks Forecast Office of the National Weather Service and the Alaska Climate Research Center, with contributions by Ted Fathauer, Anton Prechtel, Blake Moore. Portions of this summary appear in Weatherwise magazine. Preliminary climatological data are used for the graphical products. For official data, please contact us or the National Climatic Data Center. |
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