194  
SRAK48 PACR 052047  
RVAAK  
AKZALL-232200-  
 
ALASKA SPRING BREAKUP SUMMARY  
NWS ALASKA PACIFIC RIVER FORECAST CENTER ANCHORAGE AK  
1 PM AKDT JUN 5 2018  
   
..SPRING BREAKUP SUMMARY FOR ALASKA.
 
 
FLOOD WARNING/WATCHES:  
FLOOD ADVISORIES ISSUED FOR THE COLVILLE RIVER AT NUIQSUT TO THE DELTA AND THE  
KUPARUK RIVER AT THE BRIDGE  
 
BREAKUP ON THE NORTH SLOPE IS JUST ABOUT OVER WITH ICE STILL PRESENT IN THE  
RIVERS NEAR THE COAST. TEMPERATURES HAVE RISEN RESULTING IN WATER LEVEL RISES  
ON THE SAG RIVER, COLVILLE AND KUPARUK RIVERS. A SMALL ICE JAM WAS REPORT ALONG  
THE COLVILLE RIVER NEAR OCEAN POINT. THIS JAM HAS PERSISTED FOR SEVERAL DAYS.  
WATER LEVELS DOWNSTREAM ARE EXPECTED TO RISE WHEN THE JAM RELEASES BUT NO  
FLOODING BEYOND THE CURRENT SITUATION IS EXPECTED.  
 
STATEWIDE BREAKUP FLOOD POTENTIAL FORECAST-  
 
BREAKUP IN ALASKA HAS COMPLETED WITH THE EXCEPTION OF THE NORTH  
SLOPE. THE FLOOD POTENTIAL FROM SNOWMELT AND ICE JAMS THROUGHOUT  
MOST OF ALASKA THIS SPRING WAS RATED AS LOW TO LOW-MODERATE  
INDICATING THAT LOCATIONS THAT OFTEN EXPERIENCE FLOODING DURING  
BREAKUP MAY HAVE SEEN MINOR FLOODING IF AN ICE JAM FORMED  
DOWNSTREAM. THE CENTRAL TANANA VALLEY HAD A HIGHER RISK OF MINOR  
FLOODING THIS SPRING DUE TO A GREATER THAN NORMAL WINTER SNOWPACK.  
 
WEATHER - NORTH SLOPE TEMPERATURES ARE EXPECTED TO REMAIN ABOVE FREEZING  
DURING THE DAY AND FALLING SLIGHTLY BELOW FREEZING AT NIGHT OVER THE NEXT FEW  
DAYS.  
 
RECENT BREAKUP ACTIVITY ACROSS THE STATE:  
 
********************************************************************  
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... OPEN  
 
SKWENTNA AND YENTNA RIVER.. OPEN  
 
COPPER RIVER.. OPEN  
 
TANANA RIVER.. OPEN  
 
KUSKOKWIM... OPEN  
 
YUKON RIVER... OPEN  
 
KOYUKUK RIVER... OPEN  
 
KOBUK RIVER... OPEN  
 
NOATAK RIVER... OPEN  
 
BROOKS RANGE - NORTH...  
(6/4) NEAR THE COAST, RIVER ICE REMAINS PRESENT. THE ICE JAM ALONG THE COLVILLE  
RIVER REMAINS BUT POSES NO IMMEDIATE THREAT TO FLOODING.  
 
FOR MORE DETAIL AND TO SEE A FLOOD POTENTIAL MAP REFER TO OUR WEB  
SITE AT HTTPS://WWW.WEATHER.GOV/APRFC/FLOODPOTENTIAL  
 
---------------------------------------------------------------------  
SNOWMELT RUNOFF VOLUME: EXPECTED WATER VOLUME FROM SNOWMELT DURING  
THE MELT SEASON.  
 
FLOOD POTENTIAL: THE LIKELIHOOD OF FLOODING FROM SNOWMELT AND/OR  
ICE JAMS. THIS IS INITIALLY CALCULATED BASED ON THE FLOOD FREQUENCY  
FOR THE 2000 TO 2017 HISTORICAL RECORD AND ADJUSTED TO REFLECT  
CURRENT CONDITIONS.  
 
* AVERAGE (MEDIAN) BREAKUP DATES ARE FOR THE PERIOD 1980 THROUGH  
2017 AND ARE CALCULATED FOR LOCATIONS WITH AT LEAST 5 YEARS OF DATA.  
** ACTUAL BREAKUP DATE FOR THIS YEAR  
 
---------------------------------------------------------------------  
 
SNOWMELT FLOOD AVERAGE NO. OF FORECAST  
RIVER - REACH RUNOFF POTENTIAL BREAKUP YEARS BREAKUP  
VOLUME DATE* USED DATE  
------------- ---------- --------- ------- ------ --------  
SOUTHEAST PANHANDLE BELOW  
 
KENAI RIVER BELOW LOW  
 
ANCHOR RIVER BELOW LOW  
 
MATANUSKA RIVER AVERAGE LOW  
 
SUSITNA RIVER AVERAGE  
GOLD CREEK LOW  
SUNSHINE LOW 05/03 29 **05/04  
 
YENTNA RIVER BELOW  
LAKE CREEK LOW 05/01 27 **05/03  
 
SKWENTNA RIVER BELOW  
SKWENTNA LOW 04/30 23 **05/03  
 
COPPER RIVER BASIN ABOVE AVERAGE  
GAKONA RVR @ HWY LOW 04/30 30 **05/06  
GULKANA RVR @ HWY LOW 04/30 29 **05/06  
 
CHENA RIVER ABOVE AVERAGE  
CHENA LAKES PROJECT  
FAIRBANKS LOW 04/26 26  
 
TANANA RIVER ABOVE AVERAGE  
CHISANA @ NORTHWAY LOW 04/26 27 **04/25  
SALCHA LOW  
FAIRBANKS LOW 04/29 19 **04/27  
NENANA LOW 04/30 38 **05/01  
MANLEY LOW 05/03 27 **05/07  
 
KUSKOKWIM RIVER AVERAGE  
NIKOLAI LOW 04/23 32 **04/24  
MCGRATH LOW-MOD 05/04 38 **05/09  
STONY RIVER LOW 05/02 30 **05/02  
SLEETMUTE LOW-MOD 05/02 29 **04/29  
RED DEVIL LOW-MOD 05/04 32 **04/29  
CROOKED CREEK LOW-MOD 05/05 32 **04/30  
ANIAK LOW-MOD 05/07 35 **05/01  
KALSKAG LOW 05/07 29 **05/05  
TULUKSAK LOW 05/07 26 **05/04  
AKIAK LOW 05/09 32 **05/04  
KWETHLUK LOW-MOD 05/10 6 **04/30  
BETHEL LOW 05/10 38 **05/03  
NAPAKIAK LOW 05/11 23 **05/05  
 
YUKON RIVER (UPPER) AVERAGE  
DAWSON, YT LOW 05/04 38 **05/08  
EAGLE LOW 05/04 37 **05/08  
CIRCLE LOW-MOD 05/08 34 **05/10  
FORT YUKON LOW 05/10 34 **05/11  
BEAVER LOW 05/10 22 **05/12  
STEVENS VILLAGE LOW 05/11 21 **05/11  
RAMPART LOW 05/11 23 **05/12  
 
YUKON RIVER (MIDDLE) ABOVE AVERAGE  
TANANA LOW 05/08 33 **05/07  
RUBY LOW 05/09 32 **05/12  
GALENA LOW-MOD 05/11 37 **05/12  
KOYUKUK LOW-MOD 05/10 13 **05/13  
NULATO LOW-MOD 05/10 22 **05/13  
KALTAG LOW 05/12 32 **05/14  
ANVIK LOW 05/14 31 **05/15  
 
YUKON RIVER (LOWER) ABOVE AVERAGE  
HOLY CROSS LOW 05/15 31 **05/16  
RUSSIAN MISSION LOW 05/16 32 **05/14  
MARSHALL LOW-MOD 05/15 26 **05/15  
PILOT STATION LOW 05/15 21 **05/13  
MOUNTAIN VILLAGE LOW 05/19 31 **05/14  
ALAKANUK/EMMONAK LOW-MOD 05/21 32 **05/18  
 
KOYUKUK RIVER ABOVE AVERAGE  
BETTLES LOW 05/09 36 **05/11  
ALLAKAKET LOW 05/09 32 **05/11  
HUGHES LOW-MOD 05/11 31 **05/11  
 
SEWARD PENINSULA ABOVE AVERAGE  
BUCKLAND LOW-MOD 05/20 28 **05/12  
 
KOBUK RIVER ABOVE AVERAGE  
KOBUK LOW-MOD 05/14 34 **05/11  
SHUNGNAK LOW 05/17 28 **05/16  
AMBLER LOW 05/17 34 **05/16  
 
NOATAK RIVER ABOVE AVERAGE  
NOATAK LOW 05/19 22 **05/15  
 
BROOKS RANGE - NORTH AVERAGE  
COLVILLE @ UMIAT LOW 05/25 18 05/23-05/29  
COLVILLE @ COLVILLE VILLAGE LOW 06/03 20 05/31-06/05  
 
SAGAVANIRKTOK RIVER AVERAGE  
DALTON HWY LOW  
 
THIS WILL BE THE LAST BREAKUP SUMMARY FOR THE 2018 BREAKUP SEASON.  
 

 
EHM  
 
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