Flood Potential Outlook
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ESFAK

HYDROLOGIC OUTLOOK
NWS ALASKA PACIFIC RIVER FORECAST CENTER ANCHORAGE AK
3 PM AKDT THU MAR 23 2017

..SPRING BREAKUP OUTLOOK FOR ALASKA...

The flood potential from snowmelt and ice jams throughout Alaska this
spring is currently rated as normal.  This would indicate that
locations that often experience flooding during breakup are likely to
see minor flooding if an ice jam forms downstream. This forecast is
based on current ice thickness, observed snowpack, river freeze-up
stage, and long range weather forecasts.

Ice conditions

March ice thickness data are available for a limited number of
observing sites in Alaska. March 1st measurements indicate that ice
thickness is generally normal to slightly above normal across most of
the state with two exceptions.  The ice on the Yukon River at Galena
was significantly thicker than normal and the ice thickness measured
on the Colville River at Colville Village was below normal.
Accumulated freezing degree days trend from below normal along the
North Slope of Alaska to near normal in the interior of Alaska to
above normal in Southcentral and Southeast Alaska.

Snowpack

An analysis of the March 1st snowpack by the Natural Resources
Conservation Service (NRCS) indicates a generally below normal
snowpack south of the Alaska Range, including Southeast Alaska. Areas
along the Southern slopes of the western Alaska Range are well below
average.  North of the Alaska Range, there is an area of well above
normal snowpack east of Fairbanks, but overall averages within the
Middle and Upper Yukon basins are close to normal.  Snowpack
conditions along the Dalton highway on the North Slope of Alaska are
near normal. The month of March continues to be unusually dry for
areas South of the Alaska Range and along the West Coast of Alaska.
For more details, please refer to the various snow graphics from the
Alaska-Pacific River Forecast Center (APRFC) or from the Natural
Resources Conservation Service (NRCS).

Climate Outlook

The most important factor determining the severity of ice breakup
remains the weather during April and May.  The temperature outlook
through March indicates an increased chance for above normal
temperatures in Southern and Eastern areas of Alaska. The temperature
outlook through April suggests an increased chance of above normal
temperatures for Southern and Western portions of the state with
equal chances of above or below normal temperatures for Northeast
areas of the State. It should be noted that forecast confidence
through this period is low as model results have been quite variable
lately.
  For more information on the climate forecasts please refer to the
Climate Prediction Center. The next spring outlook is scheduled for
Thursday April 6th.

$$
bcj



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