Example of the existing spring breakup summary text product is provided below. Newer format spring breakup summary products are
available here: https://www.weather.gov/aprfc/breakup
For questions or comments please email Celine van Breukelen at celine.vanbreukelen@noaa.gov
460
SRAK48 PACR 291538 RRA
RVAAK
Alaska Spring Breakup Summary
NWS Alaska Pacific River Forecast Center
Anchorage
0740 AM AKDT Mon May 29 2023
...RECENT NOTABLE EVENTS OR FORECAST CHANGES...
Flood watches and warnings are in effect on the Yukon River from
Russian Mission down to the coast. Water levels are expected
to remain high for a couple of weeks. For more specific details
regarding the flood products go to www.weather.gov/aprfc/FLOOD.
Kuskokwim River levels continue to drop slowly as the tundra
drains.
...SPRING BREAKUP SUMMARY FOR ALASKA...
Breakup in Alaska this year continues to be delayed.
The spring breakup flood potential for major rivers in Alaska:
Yukon River: Above average
Koyukuk River: Above average
Kuskokwim River: Above average
Susitna River: Above average
Tanana River and Chena River: Above average
North Slope rivers: Average
Copper Basin rivers: Average
This outlook is based on observed snowpack, ice thickness reports,
and seasonal temperature outlooks. It is important to remember that
while Alaska has experienced mostly mild winters for the past
decade, 'average' is defined over a longer period. Average flood
potential may be higher than in recent memory.
...River Ice...
The following are end of winter ice conditions and are listed as
an indication of the total ice thickness before melt.
River ice observations are available for a limited number of
observing sites in Alaska. Measurements so far through April show
slightly thinner than average ice thicknesses across most of the
state. Ice measurements in the Interior are generally 70-90% of
average, with only the Tanana River at Fairbanks reporting above
average ice thicknesses at 130% of average. On the Kuskokwim River,
observers reported thinner than average ice due to early season snow
and a mild start to the winter with one localized freeze up jam
resulting in thicker ice between Kalskag and Aniak. A series of
freeze-up jams on the Upper Yukon River resulted in high water levels
during freeze up with rough ice that is reported thicker than average.
...Snowpack...
Analysis of the May 1st snowpack by the Natural Resources Conservation
Service (NRCS) indicates an above normal snowpack for Alaska.
Snowpack estimates for major rivers basins in Alaska:
Arctic: Slightly above normal
Upper Yukon Basin (largely in Canada): 173% of normal
Central Yukon Basin: 174% of normal
Tanana Basin: 222% of normal
Koyukuk Basin: 178% of normal
Lower Yukon Basin: 210% of normal
Upper Kuskokwim Basin: Above normal
Lower Kuskokwim Basin: Above normal
Copper River Basin: 179% of normal (averaged across basin)
Matanuska and Susitna Basins: 140% of normal
Kenai Basin: 140% of normal; lowest amounts along Turnagain Arm
...Climate Outlook...
Current weather models and NOAA's climate Prediction Center (CPC)
outlook for the state through June 9th indicates that SW Alaska will
continue to be colder than climate normal and transition as we move north
to above climate normal through the Brooks Range and across the North
Slope.
For more climate information: www.cpc.ncep.noaa.gov
...Flood Potential...
The following table gives an estimation of flood potential for
various locations around Alaska and basin runoff volumes.
--------------------------------------------------------------------
SNOWMELT RUNOFF VOLUME...EXPECTED WATER VOLUME FROM SNOWMELT DURING
THE MELT SEASON.
FLOOD POTENTIAL...THE LIKELIHOOD OF FLOODING FROM SNOWMELT AND/OR
ICE JAMS.
* Median breakup dates are for the period 1980 through 2021 and are
calculated for locations with at least 5 years of data.
** Actual breakup date for the current year.
--------------------------------------------------------------------
SNOWMELT FLOOD MEDIAN NO. OF FORECAST
RIVER - REACH RUNOFF POTENTIAL BREAKUP YEARS BREAKUP
VOLUME DATE* USED DATE
------------- ---------- ---------- ------- ------ ---------
SOUTHEAST PANHANDLE AVERAGE
KENAI RIVER BELOW LOW
ANCHOR RIVER BELOW LOW 04/17 16 04/20**
MATANUSKA RIVER ABOVE LOW-MOD
SUSITNA RIVER ABOVE
GOLD CREEK MOD 05/09**
SUNSHINE LOW-MOD 05/02 34 05/10**
YENTNA RIVER ABOVE
LAKE CREEK LOW-MOD 05/01 31 05/10**
SKWENTNA RIVER ABOVE
SKWENTNA LOW-MOD 04/29 28 05/07**
COPPER RIVER BASIN ABOVE
GAKONA @ HWY LOW-MOD 04/29 34 05/05**
GULKANA @ HWY LOW-MOD 04/29 33 05/02**
CHENA RIVER ABOVE
FAIRBANKS LOW-MOD 04/25 30 04/30**
TANANA RIVER ABOVE
CHISANA @ NORTHWAY LOW-MOD 04/25 32 05/03**
SALCHA LOW-MOD 04/30**
FAIRBANKS LOW-MOD 04/29 21 05/09**
NENANA LOW-MOD 04/29 43 05/08**
MANLEY MOD 05/03 31 05/12**
KUSKOKWIM RIVER ABOVE
NIKOLAI LOW 04/23 37 05/02**
MCGRATH MOD 05/03 43 05/13**
STONY RIVER LOW-MOD 05/02 35 05/12**
SLEETMUTE MOD 05/01 34 05/13**
RED DEVIL MOD 05/03 37 05/13**
CROOKED CREEK MOD 05/03 37 05/13**
ANIAK MOD-HIGH 05/06 40 05/15**
KALSKAG MOD-HIGH 05/05 34 05/15**
TULUKSAK LOW-MOD 05/07 31 05/18**
AKIAK LOW-MOD 05/07 37 05/18**
KWETHLUK MOD 05/03 11 05/20**
BETHEL LOW-MOD 05/09 43 05/20**
NAPAKIAK LOW-MOD 05/10 28 05/20**
YUKON RIVER (UPPER) ABOVE
DAWSON, YT LOW-MOD 05/04 43 05/09**
EAGLE MOD 05/04 43 05/12**
CIRCLE MOD-HIGH 05/09 39 05/13**
FORT YUKON MOD 05/11 39 05/14**
BEAVER LOW -MOD 05/11 26 05/15**
STEVENS VILLAGE MOD 05/11 24 05/15**
RAMPART LOW-MOD 05/11 26 05/16**
YUKON RIVER (MIDDLE) ABOVE
TANANA MOD 05/07 38 05/14**
RUBY LOW 05/09 37 05/17**
GALENA MOD 05/11 42 05/19**
KOYUKUK MOD 05/10 16 05/17**
NULATO MOD 05/11 25 05/18**
KALTAG LOW-MOD 05/11 37 05/18**
ANVIK LOW-MOD 05/14 34 05/19**
YUKON RIVER (LOWER) AVERAGE
HOLY CROSS LOW-MOD 05/14 36 05/20**
RUSSIAN MISSION LOW-MOD 05/15 36 05/25**
MARSHALL LOW-MOD 05/15 31 05/25**
PILOT STATION LOW 05/14 26 05/25**
MOUNTAIN VILLAGE LOW 05/14 36 05/23**
EMMONAK MOD 05/19 37 05/28**
ALAKANUK 05/28-05/30
KOYUKUK RIVER ABOVE
BETTLES LOW 05/10 41 05/13**
ALLAKAKET LOW-MOD 05/11 36 05/14**
HUGHES LOW-MOD 05/11 36 05/14**
SEWARD PENINSULA ABOVE
BUCKLAND MOD-HIGH 05/15 33 05/19**
KOBUK RIVER ABOVE
KOBUK MOD 05/14 39 05/20**
SHUNGNAK LOW 05/15 32 05/21**
AMBLER LOW 05/15 38 05/21**
NOATAK RIVER ABOVE
NOATAK LOW-MOD 05/19 25 05/27-05/29
BROOKS RANGE - NORTH BELOW
COLVILLE @ UMIAT LOW 05/26 20 05/22**
COLVILLE @ COLVILLE LOW 06/04 22 06/01-06/07
SAGAVANIRKTOK RIVER AVERAGE
DALTON HWY LOW
FOR MORE DETAIL AND TO SEE A FLOOD POTENTIAL MAP REFER TO OUR WEB
SITE AT HTTPS://WWW.WEATHER.GOV/APRFC/FLOODPOTENTIAL
The breakup summary will be issued daily.
Visit us at http://www.weather.gov/aprfc
$$
jf
