River Summary
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SRAK48 PACR 202057
RVAAK
AKZALL-202200-

ALASKA SPRING BREAKUP SUMMARY
NWS ALASKA PACIFIC RIVER FORECAST CENTER ANCHORAGE AK
100 PM ADT May 20 2019

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

FLOOD WARNING/WATCHES:
A flood advisory has been issued for minor flooding on the Porcupine
river downstream of the Canadian Border to Fort Yukon.

ALASKA BREAKUP SUMMARY NOTABLE EVENTS FROM PAST 24 HOURS -
Most rivers south of the Brooks range are now open although there are
some heavy ice runs traveling down the Koyukuk River and still some
light runs of ice traveling downstream on the Yukon.  The Porcupine river
is beginning to breakup and satellite images showed a run of ice moving
downstream from the Canadian border on 5/15. Water levels were very high
at the border and will likely lead to out of bank water and minor flooding
down to Fort Yukon. Water levels on the upper Porcupine River are now falling.
Water levels on the Old Crow River continue to rise and ice floes continue.

Temperatures in the interior are rising above normal with below normal
precipitation expected over the next few weeks. Continued snowmelt
and runoff will accelerate river breakup process where ice is still present
and cause rivers to rise.

STATEWIDE BREAKUP FLOOD POTENTIAL FORECAST-
Flood potential statewide generally is low with the exception being on
the North Slope where the flood threat is normal due to the large
snowpack.

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...
Satellite images and observer reports indicate the Susitna River is
open.

SKWENTNA AND YENTNA RIVER...
Skwentna River and Yentna river are open.

COPPER RIVER...
The Copper River is open.

TANANA RIVER...
The Tanana River is open.

KUSKOKWIM...
The Kuskokwim River is open.

YUKON RIVER...
Much of the Yukon is now open, but expect ice runs to continue coming
down from upriver.

KOYUKUK RIVER...
Breakup on the Koyukuk has occurred but there are several runs of ice
passing downstream past Bettles and Allakaket. Water levels at Bettles
and Allakaket are high as significant snowmelt hits the river channels.

KOBUK RIVER...
The Kobuk River at Kobuk broke up Tuesday 5/14. Ice started moving at
Ambler at 1:30 am Thursday 5/16 and was still moving by on Thursday
afternoon.

NORTH SLOPE...
Breakup is just beginning on the North Slope.

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.  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 2018
   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         BELOW   LOW

SUSITNA RIVER           BELOW
  GOLD CREEK                      LOW
  SUNSHINE                        LOW       05/03     30      OPEN

YENTNA RIVER            BELOW
  LAKE CREEK/FISH CREEK           LOW       05/01     27    **04/15

SKWENTNA RIVER          BELOW
  SKWENTNA                        LOW       04/30     24    **04/12

CHENA RIVER             BELOW

  FAIRBANKS                       LOW       04/26     27     OPEN

TANANA RIVER            BELOW
  CHISANA @ NORTHWAY              LOW       04/26     28    **04/10
  SALCHA                          LOW
  FAIRBANKS                       LOW       04/29     19    **04/16
  NENANA                          LOW       04/30     39    **04/14
  MANLEY                          LOW       05/03     28    **04/30

KUSKOKWIM RIVER         BELOW
  NIKOLAI                         LOW       04/23     34    **03/31
  MCGRATH                         LOW       05/05     39    **04/28
  STONY RIVER                     LOW       05/02     31    **04/28
  SLEETMUTE                       LOW       05/02     30    **04/28
  RED DEVIL                       LOW       05/04     33    **04/29
  CROOKED CREEK                   LOW       05/04     33    **04/29
  ANIAK                           LOW       05/06     36    **04/29
  KALSKAG                         LOW       05/06     30    **04/29
  TULUKSAK                        LOW       05/07     27    **04/30
  AKIAK                           LOW       05/09     33    **04/26
  KWETHLUK                        LOW       05/05      7    **04/07
  BETHEL                          LOW       05/10     39    **04/12
  NAPAKIAK                        LOW       05/11     24    **04/14

YUKON RIVER (UPPER)    BELOW
  DAWSON, YT                      LOW       05/04     39    **04/23
  EAGLE                           LOW       05/04     38    **05/01
  CIRCLE                          LOW       05/08     35    **05/09
  FORT YUKON                      LOW       05/11     35   **05/11 apprx
  BEAVER                          LOW       05/10     23    **05/12
  STEVENS VILLAGE                 LOW       05/11     22    **05/12
  RAMPART                         LOW       05/11     24    **05/12

YUKON RIVER (MIDDLE)   BELOW
  TANANA                          LOW       05/08     34    **05/05
  RUBY                            LOW       05/09     33    **05/08
  GALENA                          LOW       05/11     38    **05/08
  KOYUKUK                         LOW       05/10     13    **05/08
  NULATO                          LOW       05/11     23    **05/08
  KALTAG                          LOW       05/12     33    **05/12
  ANVIK                           LOW       05/14     32    **05/13

YUKON RIVER (LOWER)    BELOW
  HOLY CROSS                      LOW       05/15     32    **05/05
  RUSSIAN MISSION                 LOW       05/16     33    **05/05
  MARSHALL                        LOW       05/15     27    **05/05
  PILOT STATION                   LOW       05/14     22  **05/07 apprx
  MOUNTAIN VILLAGE                LOW       05/17     32    **05/08
  ALAKANUK/EMMONAK                LOW       05/21     32    **05/08

KOYUKUK RIVER          ABOVE
  BETTLES                         LOW       05/10     37    **05/14
  ALLAKAKET                       LOW       05/10     33    **05/14
  HUGHES                        LOW-MOD     05/11     32    **05/12

SEWARD PENINSULA       ABOVE
  BUCKLAND                      LOW-MOD     05/19     29    **05/05

KOBUK RIVER            ABOVE
  KOBUK                         LOW-MOD     05/14     35    **05/14
  SHUNGNAK                        LOW       05/17     29    **05/16
  AMBLER                          LOW       05/17     35    **05/16

NOATAK RIVER           ABOVE
  NOATAK                          LOW       05/19     23  **05/10 apprx

BROOKS RANGE - NORTH   ABOVE
  COLVILLE @ UMIAT                LOW       05/25     18  05/18-05/22
  COLVILLE @ COLVILLE             LOW       06/04     21  05/26-06/02

SAGAVANIRKTOK RIVER    ABOVE
  DALTON HWY                    LOW-MOD


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

THE NEXT SPRING BREAKUP OUTLOOK IS SCHEDULED AT 2 PM ADT Tue May 21 2019.

$$
ehm


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