National Weather Service United States Department of Commerce

000
SRAK48 PACR 262302
RVAAK
AKZALL-232200-

ALASKA SPRING BREAKUP SUMMARY
NWS ALASKA PACIFIC RIVER FORECAST CENTER ANCHORAGE AK
4 PM AKDT May 26 2018

...SPRING BREAKUP SUMMARY FOR ALASKA....

FLOOD WARNING/WATCHES:
NONE AT THIS TIME.

ALASKA BREAKUP SUMMARY NOTABLE EVENTS FROM PAST 24 HOURS -
NO NEW INFORMATION SINCE YESTERDAY.
BREAKUP ON THE NORTH SLOPE IS PROCEEDING SLOWLY. TEMPERATURES ARE ON
THE COOL SIDE, WITH BELOW NORMAL TEMPERATURES AT SAGWON AND PRUDHOE
BAY, AND WATER LEVELS REMAIN LOW. WATER ON THE COLVILLE RIVER IS
BEGINING TO RISE ALONG THE LOWER REACH NEAR NUIQSUIT. CHANNEL ICE ON
THE COLVILLE RIVER IS STILL INTACT ALONG THE LOWER REACH. FLOW ON
THE SAG RIVER IS BEGINNING TO INCREASE BASED ON MANUAL MEASUREMENTS
AND WEBCAM IMAGERY.

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 BE IN THE 30S FOR
THE NEXT FEW DAYS WITH A HIGH IN THE MID 40`S ON MEMORIAL DAY.

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... (5/23) WATER ON THE COLVILLE RIVER IS STILL
MOSTLY ICE COVERED.  BEGINING TO RISE ALONG THE LOWER REACH NEAR
NUIQSUIT. CHANNEL ICE ON THE COLVILLE RIVER IS STILL INTACK ALONG
THE LOWER REACH. FLOW ON THE SAG RIVER IS RISING BASED ON MANUAL
MEASUREMENTS.
(5/21) BASED ON PHOTOS FROM USGS AND WEBCAM IMAGES BREAKUP IS
BEGINNING ON THE NORTH SLOPE. SOME WATER HAS MOVED DOWN THE COLVILLE
AS FAR AS COLVILLE VILLAGE BUT SO FAR PROGRESS IS SLOW AND WATER
LEVELS ARE RELATIVELY LOW.
(5/20) WATER IS PROGRESSING ON TOP OF ICE TOWARDS THE ARCTIC OCEAN
ON THE NORTH SLOPE RIVERS SUCH AS THE COLVILLE AND KUPARUK. (5/16)
AN OPEN LEAD HAS FORMED ALONG THE SAGAVANIRKTOK RIVER ALONG THE
DALTON HIGHWAY.

FOR MORE DETAIL AND TO SEE A FLOOD POTENTIAL MAP REFER TO OUR WEB
SITE AT HTTPS://WWW.WEATHER.GOV/APRFC/FLOODPOTENTIAL


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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


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                      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

THE NEXT SPRING BREAKUP SUMMARY IS SCHEDULED AT 2 PM AKDT Sunday,
MAY 27, 2018


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CVB