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Monday, January 27, 2014

Jeff Masters: Record-breaking heat in Alaska, some of the largest avalanches ever observed in that region

by Jeff Masters, wunderblog, January 27, 2014

If you're wondering where California's missing precipitation has been going, look northwards to the south and southeast coasts of Alaska. The remarkably persistent ridge of high pressure that has blocked rain from falling in California during January has shunted all the rain-bearing low pressure systems northward, bringing exceptionally warm and wet weather to coastal Alaska. 

Heavy rains, snows, and warm temperatures helped trigger a‪ series of huge avalanches that began on Friday, which blocked a 52-mile long section of the ‬Richardson Highway, the only road into Valdez, Alaska (population 4,000), located about 120 miles east of Anchorage. 

The avalanches, called some of the largest avalanches ever observed in the region, blocked the Lowe River in Keystone Canyon, creating a large backup of water behind the snow and ice dam. The water level is slowly dropping, but a Flash Flood Watch has been posted for the region in case the avalanche dam suddenly releases. The highway is expected to be cleared no earlier than February 2, according to the city of Valdez website. Extra marine ferries will be running during the blockage to provide supplies to Valdez.

Figure 1. ‪The ‬Richardson Highway, the only road into Valdez, Alaska, lies blocked by a massive avalanche in this January 25, 2014, photo from the Alaska Department of Transportation and Public Facilities.

Record warmth and precipitation in Alaska
As of January 26, 13.83" of precipitation had fallen in Valdez during the month of January. This is more than 8" above average for this point in the month, and close to the all-time record for January precipitation of 15.18", set in 2001 (records go back to 1972.) With more rain on the way Monday and Tuesday, this record could easily fall. Numerous locations in Southeast Alaska have beaten their rainiest January day on record marks.

Wunderground's weather historian Christopher C. Burt has much more detail on the record Alaska January warmth in his latest post, Record Warmth in Alaska Contrasts Cold Wave in Eastern U.S. A few highlights:

- Temperatures of up to 40 degrees above normal occurred across the interior and West Coast of Alaska on Sunday. Bolio Lake Range Complex in Fort Greely, Alaska, located about 100 miles southeast of Fairbanks, hit 60 °F. This is only 2 °F short of the all-time state January heat record of 62 °F set at Petersburg in 1981.

- At 10 p.m. local time Sunday in Homer, Alaska, the temperature was 54 °F. This was warmer than any location in the contiguous U.S., except for Southern Florida and Southern California. The 55 °F high in Homer on Sunday broke their all-time monthly record by 4 °F. 

- All-time January heat records have been set in 2014 in Nome, Denali Park, Palmer, Homer, Alyseka, Seward, and Talkeetna.

Video 1. ‪Valdez Alaska: Massive Avalanche and ice dam in Keystone Canyon‬. This clip shows a flyover of the avalanche in Keystone Canyon blocking the Lowe River, January 26, 2014. Video courtesy of Vertical Solutions.

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