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Public Information Statement
Issued by NWS Seattle/Tacoma, WA

000
NOUS46 KSEW 142112
PNSSEW

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE SEATTLE WA
210 PM PDT FRI JUN 14 2013

...CAUTION ADVISED HIKING MOUNT BAKER...

ON MAY 31 2013...A SMALL LANDSLIDE OFF THE NORTH VALLEY WALL SENT
ROCK DEBRIS INTO MIDDLE FORK NOOKSACK RIVER NEAR THE TOE OF GLACIER.
THE WATER/ROCK MIXTURE BECAME A DEBRIS FLOW THAT RUSHED DOWN VALLEY
MORE THAN THREE MILES NEAR THE ELBOW LAKE TRAIL CROSSING. TWO
SMALLER DEBRIS FLOWS OCCURRED ON JUNE 1 AND 6. EVENTS ARE
IDENTIFIABLE ON RECORDS OF SEISMICITY...TURBIDITY AND RIVER
DISCHARGE.

DEBRIS FLOWS ARE FAST-MOVING SLURRIES OF BOULDERS AND MUD. THEY ARE
SPORADIC EVENTS IN THE VALLEYS OF GLACIATED VOLCANOES DUE TO THE
ABUNDANCE OF LOOSE VOLCANIC ROCK...EXCESS WATER...STEEP SLOPES...AND
CONFINING VALLEY WALLS. EVENTS ARE NOT UNCOMMON AT MOUNT RAINIER AND
AT MOUNT HOOD...FOR EXAMPLE...AND HAVE HAPPENED BEFORE ON MOUNT
BAKER AND NEARBY GLACIER PEAK.

THE RIVER CHANNEL COULD BE REWORKED FOR YEARS AS STREAM WATER
TRANSPORTS AND REDISTRIBUTES THE ROCK DEBRIS. THE CHANNEL ROCKS
COULD BE ON THE MOVE FOR QUITE A FEW MORE YEARS. TRANSPORT OF ROCKS
BY DEBRIS FLOWS AND RIVER TRANSPORT WILL TRANSFORM THIS ONCE STABLE
UPPER PORTION OF THE MIDDLE FORK NOOKSACK RIVER VALLEY INTO A
DYNAMIC AND CHANGING LANDSCAPE.

RIVER USERS MIGHT SEE TURBID WATER IN THE MIDDLE FORK NOOKSACK RIVER
AS THE RIVER TRANSPORTS LOOSE DEBRIS DOWNSTREAM IN YEARS TO COME.

SAFETY:
IF YOU ARE ON THE VALLEY FLOOR OF MIDDLE FORK NOOKSACK RIVER AND
FEEL APPROACHING RUMBLING AND HEAR THE ROAR...MOVE STRAIGHT TO
HIGHER GROUND IMMEDIATELY..OFF THE VALLEY FLOOR. YOU CANNOT OUTRUN A
DEBRIS FLOW...AS THEY COMMONLY MOVE AT SPEEDS OF 20 MPH OR MORE.

PRESENTLY...IMPOUNDED WATER PUTS HIKERS IN THE RIDLEY CREEK AND
ELBOW LAKE TRAIL AREAS AT RISK...BUT THERE IS NO RISK TO DOWNSTREAM
RESIDENTS. FUTURE DEBRIS FLOWS AND FLASH FLOODS ARE POSSIBLE
PERIODICALLY AS WATER MOVES DOWN VALLEY.

THE FOREST SERVICE IS POSTING SIGNS TO MAKE HIKERS AWARE OF THE
HAZARD AROUND RIDLEY CREEK CROSSING AND ELBOW LAKE TRAIL. UNSTABLE
BOULDERS AND MUD-SLICKENED ROCKS REMAIN FROM THE DEBRIS FLOW AND
MAKE THE STREAM CHANNEL HAZARDOUS FOR WALKING. STAY AWAY FROM THE
AREA...OR IF YOU MUST BE THERE...BE READY TO ESCAPE THE VALLEY FLOOR
QUICKLY.

IMPORTANT: AT PRESENT...THERE IS NO INCREASED THREAT FOR PEOPLE
BEYOND MORE THAN A FEW MILES DOWN VALLEY OF RIDLEY CREEK CROSSING
AND ELBOW LAKE TRAIL AREAS...BUT PEOPLE SHOULD ALWAYS BE COGNIZANT
OF THE INHERENT RISKS OF LIVING ALONG A RIVER (FLOODS...AND LAHARS
DURING VOLCANIC ERUPTIONS).

***SCIENTISTS FROM MULTIPLE AGENCIES AND INSTITUTIONS ARE
COORDINATING OBSERVATIONS AND MAKING PLANS FOR FURTHER MONITORING OF
THE AFFECTED AREA. PRINCIPALS ARE FROM MOUNT BAKER-SNOQUALMIE
NATIONAL FOREST...NOOKSACK TRIBE...WHATCOM COUNTY...US GEOLOGICAL
SURVEY...NATIONAL WEATHER SERVICE...WESTERN WASHINGTON UNIVERSITY...
MOUNT BAKER VOLCANO RESEARCH CENTER...AND THE WASHINGTON DEPARTMENT
OF NATURAL RESOURCES.

MORE INFORMATION
MOUNT BAKER-SNOQUALMIE NATIONAL FOREST:SAFETY INFORMATION
HTTP://WWW.FS.USDA.GOV/MBS

MOUNT BAKER VOLCANO RESEARCH CENTER:
HTTP://
MBVRC.WORDPRESS.COM/2013/06/12/MORE-DEBRIS-FLOWS-IN-MIDDLE-FORK

USGS LAHARS AND DEBRIS FLOWS:
HTTP://VULCAN.WR.USGS.GOV/GLOSSARY/LAHARS/DESCRIPTION_LAHARS.HTML
YOUTUBE VIDEO CLIP OF DEBRIS FLOW AT SEMERU VOLCANO...INDONESIA

HTTP://WWW.YOUTUBE.COM/WATCH?V=KWSA2XNWK2K

MF NOOKSACK RIVER NEAR DEMING:
HTTP://ON.DOI.GOV/15HYWXX(HTTP://WATERDATA.USGS.GOV.WA/NWIS/UV/?SITE
_NO=12208000).

NWS RIVER FORECAST FOR MF NOOKSACK RIVER:
HTTP://
WWW.NWRFC.NOAA.GOV/RIVER/STATION/FLOWPLOT/FLOWPLOT.CGI?LID=MFNW1


$$

JBB