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River Summary
Issued by NWS
Issued by NWS
000
SRAK48 PACR 192223
RVAAK
AKZALL-192200-
HYDROLOGIC OUTLOOK
NWS ALASKA PACIFIC RIVER FORECAST CENTER ANCHORAGE AK
200 PM ADT SUN MAY 19 2013
...SPRING BREAKUP OUTLOOK FOR ALASKA...
THE SPRING BREAKUP FLOOD POTENTIAL THROUGHOUT ALASKA IS CURRENTLY
RATED AS MODERATE FOR MOST OF THE STATE. THIS FORECAST IS BASED ON
OBSERVED SNOWPACK...ICE THICKNESS REPORTS AND LONG RANGE TEMPERATURE
FORECASTS. SO FAR MODERATE TO MAJOR FLOODING HAS AFFECTED THE YUKON
COMMUNITIES OF EAGLE AND CIRCLE.
SHORT TERM FLOOD OUTLOOK- TEMPERATURES ARE EXPECTED TO BEGIN
APPROACHING NORMAL THIS WEEK. TOGETHER WITH LONG DAYLIGHT HOURS THIS
SHOULD BEGIN TO RESULT IN RIPENING AND MELTING OF BOTH THE RIVER ICE
AND THE REMAINING LOW LYING SNOW PACK.
ICE - MAY 1ST ICE THICKNESS MEASUREMENTS ARE AVAILABLE FOR A LIMITED
NUMBER OF SITES IN ALASKA. THEY INDICATE THAT ICE THICKNESS WAS
GENERALLY BETWEEN 100 AND 150 PERCENT OF NORMAL. ICE CONTINUES TO
SLOWLY DETERIORATE OVER MUCH OF ALASKA. AREAS WITH LONG HOURS OF
SUNSHINE MAY SHOW SOME DETERIORATION OF SNOW-FREE ICE EVEN WITH THE
COLDER TEMPERATURES.
SNOW - AN ANALYSIS OF THE MAY 1 SNOWPACK BY THE NATURAL RESOURCES
CONSERVATION SERVICE (NRCS) INDICATED A MUCH ABOVE NORMAL SNOWPACK
OVER MUCH OF THE STATE. SIGNIFICANT APRIL SNOW ACTUALLY INCREASED THE
SNOWPACK ACROSS THE STATE. THERE HAVE ALSO BEEN SNOW ACCUMULATIONS IN
THE EASTERN INTERIOR THIS WEEK WITH A CHANCE FOR ADITIONAL SNOW IN
PARTS OF THE STATE THROUGH THIS WEEKEND. THIS REMAINING SNOWPACK
COULD BE ENOUGH TO PRODUCE SIGNIFICANT SNOWMELT RUNOFF PEAKS AND
POTENTIAL FLOODING IF SUBJECTED TO A RAPID WARMING PATTERN. THIS
TYPE OF SNOWMELT FLOODING COULD OCCUR IN AREAS WHERE THE RIVER ICE
HAS ALREADY CLEARED OUT OR HAS BECOME ROTTEN IN PLACE IF THE WARMING
IS SUDDEN AND ABOVE NORMAL.
FOR MORE DETAILS ON THE SNOWPACK.. PLEASE REFER TO THE VARIOUS SNOW
GRAPH OPTIONS AT THE APRFC WEB SITE AT HTTP://APRFC.ARH.NOAA.GOV OR
ON THE NRCS WEB SITE AT
HTTP://WWW.AK.NRCS.USDA.GOV/SNOW/DATA/CURRENT.HTML
WEATHER - WARMER THAN NORMAL TEMPERATURES ARE EXPECTED ACROSS MUCH OF
THE STATE BY THE END OF THE WEEK. DYNAMIC BREAKUPS WITH A HIGH
POTENTIAL OF ICE JAM FLOODING TYPICALLY REQUIRE AN ABRUPT TRANSITION
TO WARM SUMMER-LIKE TEMPERATURES SOMETIME IN MAY. IF THE EXPECTED
WARMING TREND OCCURS THIS COULD INCREASE SNOWMELT AND CONTRIBUTE TO A
DYNAMIC BREAKUP AT LOCATIONS THAT STILL HAVE ICE ON THE RIVERS.
AREAS OF SOUTHCENTRAL ALASKA THAT RECEIVED SIGNIFICANT RAINFALL LAST
FALL LIKELY HAVE HIGHER THAN NORMAL GROUNDWATER LEVELS. THESE AREAS
ARE MORE SUSCEPTIBLE TO MINOR FLOODING AND DRAINAGE ISSUES IN THE
EVENT OF A RAPID WARM UP.
FOR MORE INFORMATION ON THE OUTLOOKS FOR THIS SPRING PLEASE REFER TO
THE CLIMATE PREDICTION CENTER WEB SITE AT
HTTP://WWW.CPC.NCEP.NOAA.GOV/INDEX.PHP
RECENT BREAKUP ACTIVITY:
*********************************************************************
*EVEN THOUGH A PARTICULAR RIVER OR REACH MAY BE DESCRIBED AS MOSTLY *
*OPEN OR OPEN... IT IS STILL POSSIBLE FOR RUNS OF ICE AND DEBRIS TO *
*MOVE THROUGH AS HEADWATERS UPSTREAM BREAKUP. PLEASE USE CAUTION AT*
*ALL TIMES WHEN ATTEMPTING TO NAVIGATE RIVERS. *
*********************************************************************
SUSITNA RIVER... THE ICE WENT OUT ON THE SKWENTNA RIVER AT SKWENTNA
BETWEEN 7 PM AND MIDNIGHT MONDAY THE 13TH. THE ICE BROKE AT YENTNA
TUESDAY EVENING THE 14TH. THE LITTLE SUSITNA IS ICE FREE AT THE GAGE
AT HOUSTON. THE SUSITNA RIVER WAS REPORTED TO HAVE OPEN LEADS
UPSTREAM FROM TALKEETNA BUT LITTLE MOVEMENT OF ICE WAS NOTED.
COPPER RIVER... THE GAKONA RIVER AT THE HIGHWAY SHOWED SIGNIFICANT
OVERFLOW OF MUDDY WATER ON TOP OF THE ICE. THE ICE IS BULGING AND
CRACKING WITH NUMEROUS OPEN LEADS. ICE JAMS HAVE BEEN NOTED ABOVE
AND BELOW THE BLUFF NEAR GAKONA.
LOWE RIVER... MOSTLY ICE FREE WITH SOME SNOW BRIDGES REMAINING ABOVE
THE CANYONS.
TANANA RIVER.. THE RIVER HAS SEVERAL OPEN LEADS FROM TANACROSS TO
FAIRBANKS AND IS MOSTLY OPEN DOWN TO NORTHWAY. AN OPEN LEAD HAS BEEN
NOTED AT THE CONFLUENCE WITH THE YUKON RIVER AS WELL.
KUSKOKWIM RIVER... THE ICE WENT OUT AT NIKOLAI THURSDAY NIGHT THE
9TH. AT THE CONFLUENCE OF THE NORTH AND SOUTH FORKS OF THE KUSKOKWIM
THERE WAS SIGNIFICANT OVERFLOW BUT NO OPEN LEADS. THE SAME CONDITIONS
WERE OBSERVED AT THE CONFLUENCE OF THE EAST AND NORTH FORKS. AT
MCGRATH THE WATER LEVEL WAS UP WITH OVERFLOW ON THE MAIN CHANNEL.
FROM MCGRATH UPSTREAM TO THE BIG RIVER THE ICE IS LIFTING...BUT THERE
WAS NO OPEN WATER. AT RED DEVIL THE WATER IS RISING AND THE MOVED
BRIEFLY ON THE 16TH. WATER LEVELS WERE ALSO RISING IN NAPAIMUTE
WITH OVERFLOW ALONG THE BANKS. AT CROOKED CREEK THE WATER FLOW ALONG
THE NORTH BANK HAS BEEN STEADILY INCREASING IN WIDTH. THERE WAS SOME
OPEN WATER IN FRONT OF ANIAK ON THE 16TH BUT IT IS BEING FILLED WITH
ICE PUSHED DOWN THE ANIAK RIVER. NO NEW REPORTS OF OPEN WATER HAVE
BEEN RECEIVED.
KOYUKUK RIVER... AT BETTLES THE SNOW WAS MELTING QUICKLY BUT THERE
WAS STILL SNOW ON THE ICE.
YUKON RIVER... AT DAWSON THE KLONDIKE RIVER WENT OUT LATE TUESDAY MAY
14TH AND PUSHED INTO THE YUKON RIVER CAUSING SOME CRACKING AND OPEN
WATER. DAWSON WENT OUT LATE WEDNESDAY THE 15TH. THE ICE MOVED IN
EAGLE AFTER MIDNIGHT AND INTO THE EARLY MORNING OF MAY 17TH BEFORE
JAMMING 12 MILES DOWNSTREAM NEAR CALICO BLUFF CAUSING MODERATE
FLOODING IN EAGLE. THE ICE JAM RELEASED ENOUGH IN THE AFTERNOON TO
ALLOW THE RIVER TO FALL BELOW FLOOD STAGE IN EAGLE. THE ICE JAM
BETWEEN EAGLE AND CIRCLE CLEARED AND A SURGE OF WATER CAUSED MAJOR
FLOODING IN CIRCLE SUNDAY MAY 19TH. THE BREAKUP FRONT IS NOW BETWEEN
CIRCLE AND FORT YUKON.
THE FOLLOWING TABLE GIVES AN ESTIMATION OF FLOOD POTENTIAL FOR
VARIOUS LOCATIONS AROUND THE STATE 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.
* AVERAGE BREAKUP DATES ARE FOR THE PERIOD 1970 THROUGH 2012 AND ARE
CALCULATED FOR LOCATIONS WITH AT LEAST 5 YEARS OF DATA.
** INDICATES ACTUAL BREAKUP DATE
---------------------------------------------------------------------
SNOWMELT FLOOD AVERAGE NO. OF FORECAST
RIVER - REACH RUNOFF POTENTIAL BREAKUP YEARS BREAKUP
VOLUME DATE * RECORD DATE
------------- ---------- --------- ------- ------ --------
SOUTHEAST PANHANDLE ABOVE
KENAI RIVER ABOVE
ANCHOR RIVER ABOVE 04/16 10
MATANUSKA RIVER ABOVE 04/30 8
SUSITNA RIVER ABOVE
GOLD CREEK LOW-MOD 05/03 9
SUNSHINE LOW-MOD 05/02 28 5/19-5/21
YENTNA RIVER AVERAGE
LAKE CREEK LOW-MOD 05/01 22 5/14**
SKWENTNA RIVER AVERAGE
SKWENTNA LOW-MOD 05/03 19 5/13**
COPPER RIVER BASIN AVERAGE
GAKONA RVR @ HWY LOW 05/02 25 5/19-5/21
GULKANA RVR @ HWY LOW 05/01 29 5/19-5/21
CHENA RIVER ABOVE
CHENA LAKES PROJECT LOW
FAIRBANKS LOW 04/28 26 5/19-5/21
TANANA RIVER ABOVE
NORTHWAY LOW 04/21 31 5/08**
SALCHA MODERATE
FAIRBANKS LOW 04/29 14 5/19-5/22
NENANA LOW-MOD 05/04 39 5/19-5/22
MANLEY LOW-MOD 05/01 23 5/19-5/22
KUSKOKWIM RIVER AVERAGE
NIKOLAI LOW 04/24 30 5/09**
MCGRATH MODERATE 05/07 39 5/16-5/21
STONY RIVER LOW 05/05 25 5/16-5/21
SLEETMUTE MODERATE 05/05 24 5/17-5/22
RED DEVIL MODERATE 05/06 27 5/17-5/22
CROOKED CREEK MODERATE 05/07 27 5/18-5/23
ANIAK MODERATE 05/08 34 5/18-5/23
KALSKAG LOW-MOD 05/08 24 5/19-5/24
TULUKSAK LOW-MOD 05/10 21 5/20-5/25
AKIAK LOW-MOD 05/10 27 5/20-5/25
KWETHLUK MODERATE
BETHEL LOW-MOD 05/12 42 5/22-5/27
NAPAKIAK LOW-MOD 05/13 19 5/23-5/28
YUKON RIVER (UPPER) ABOVE
DAWSON, YT 05/06 43 5/15**
EAGLE MODERATE 05/05 35 5/17**
CIRCLE MODERATE 05/09 31 5/19**
FORT YUKON LOW-MOD 05/10 30 5/19-5/22
BEAVER LOW 05/11 18 5/19-5/23
STEVENS VILLAGE LOW 05/12 18 5/19-5/23
RAMPART LOW 05/12 18 5/20-5/24
YUKON RIVER (MIDDLE) ABOVE
TANANA LOW-MOD 05/10 28 5/21-5/25
RUBY LOW 05/11 29 5/22-5/26
GALENA MODERATE 05/13 29 5/22-5/26
KOYUKUK MODERATE
NULATO MODERATE 05/12 17 5/23-5/27
KALTAG LOW 05/14 37 5/24-5/28
ANVIK LOW 05/16 26 5/26-5/30
YUKON RIVER (LOWER) ABOVE
HOLY CROSS LOW 05/16 26 5/26-5/30
RUSSIAN MISSION LOW 05/15 28 5/26-5/31
MARSHALL MODERATE 05/15 22 5/26-5/31
PILOT STATION LOW 05/17 16 5/27-6/01
MOUNTAIN VILLAGE LOW 05/19 26 5/28-6/02
ALAKANUK/EMMONAK MODERATE 05/23 28 5/29-6/03
KOYUKUK RIVER AVERAGE
BETTLES LOW 05/09 31 5/20-5/25
ALLAKAKET LOW 05/10 26 5/21-5/26
HUGHES MODERATE 05/10 32 5/21-5/26
SEWARD PENINSULA BELOW
BUCKLAND RIVER BELOW
BUCKLAND MODERATE 05/18 23 5/26-5/31
KOBUK RIVER BELOW
KOBUK MODERATE 05/16 33 5/24-5/29
SHUNGNAK LOW 05/18 23 5/26-5/31
AMBLER LOW 05/18 30 5/26-5/31
NOATAK RIVER BELOW
NOATAK LOW 05/20 18 5/28-6/02
ROOKS RANGE - NORTH AVERAGE
COLVILLE @ UMIAT LOW 05/24 13 6/01-6/06
COLVILLE @ COLVILLE LOW-MOD 06/01 16 6/07-6/11
FOR MORE DETAIL AND TO SEE A FLOOD POTENTIAL MAP REFER TO OUR WEB
SITE AT HTTP://APRFC.ARH.NOAA.GOV.
THE NEXT SPRING BREAKUP OUTLOOK IS SCHEDULED AT 2 PM MONDAY MAY 20.
$$
RAR
- National Weather Service
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- Page last modified: May 1st, 2013 15:31 UTC