Winter and Spring Flood Potential Outlook issued on March 20th

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WINTER/SPRING FLOOD POTENTIAL OUTLOOK
NATIONAL WEATHER SERVICE CARIBOU ME
255 PM EDT THU MAR 20 2014

...WINTER AND SPRING FLOOD POTENTIAL OUTLOOK FOR NORTHERN...
CENTRAL AND DOWNEAST MAINE...

THIS IS THE SEVENTH WINTER/SPRING FLOOD POTENTIAL OUTLOOK FOR
2014...ISSUED BY THE NATIONAL WEATHER SERVICE IN CARIBOU, MAINE.
THE WINTER/SPRING FLOOD POTENTIAL IS FOR NORTHERN, CENTRAL AND
DOWNEAST MAINE FOR THE ONE WEEK PERIOD FROM MARCH 20 TO APRIL 3,
2014.

THE WINTER/SPRING FLOOD POTENTIAL FOR ALL OF NORTHERN, CENTRAL,
AND DOWNEAST MAINE IS ABOVE NORMAL. THIS INCLUDES THE POTENTIAL
FOR FLOODING DUE TO ICE JAMS. THE ONLY EXCEPTION IS PERHAPS ALONG
THE IMMEDIATE COAST, WHERE THE FLOODING POTENTIAL IS CLOSER TO NORMAL.

...CLIMATOLOGICAL GUIDANCE...

UNSEASONABLY COLD WEATHER HAS CONTINUED TO DOMINATE THE PINE TREE
STATE OVER THE PAST WEEK. THIS HAS ALLOWED A DEEP SNOWPACK TO
REMAIN IN PLACE ACROSS MUCH OF THE STATE. THE COLD AND ACTIVE
WEATHER PATTERN WILL PERSIST INTO EARLY APRIL AS AN UPPER LOW AND
COLD AIRMASS WILL REMAIN IN PLACE OVER SOUTHERN CANADA. RECENT
STORMS HAVE TRENDED A BIT FURTHER NORTH OVER THE PAST FEW DAYS,
ALLOWING FOR RAIN TO PREVAIL OVER PORTIONS OF DOWNEAST MAINE,
ESPECIALLY ALONG THE COAST. HOWEVER, MOST OF OUR AREA HAS REMAINED
SNOW. THIS COLD AND ACTIVE PATTERN LOOKS TO PERSIST OVER THE NEXT
WEEK TO 10 DAYS, WHICH MEANS WE WILL BE CARRYING A DEEP SNOWPACK
AND PLENTY OF RIVER ICE AS WE HEAD INTO EARLY APRIL. THE OFFICIAL
NATIONAL WEATHER SERVICE 8 TO 14 DAY FORECAST DOES INDEED CALL FOR
COLDER THAN NORMAL TEMPERATURES AND WETTER THAN NORMAL CONDITIONS
FOR THE MARCH 27 THROUGH APRIL 2 TIME FRAME. HOWEVER, THERE ARE
SOME INDICATIONS THAT THE COLD WEATHER MAY BEGIN EASE UP A BIT
BEYOND THAT PERIOD. IT IS STILL TOO EARLY TO SAY FOR SURE.

...OBSERVED SNOW DEPTH AND WATER EQUIVALENTS...

SNOW DEPTHS AND THE WATER CONTAINED IN THE PACK BOTH INCREASED
DRAMATICALLY OWING TO THE STORMS THAT AFFECTED THE REGION LATE LAST
WEEK. THE STORM THAT IS JUST NOW WINDING DOWN HAS ONLY ADDED TO
THE SNOWPACK, ESPECIALLY ACROSS THE NORTH, WHILE ADDING WATER TO
THE SNOW OVER THE SOUTHERN HALF OF OUR FORECAST AREA. BEFORE THIS
CURRENT SYSTEM, NORTHERN MAINE WAS BLANKETED IN 30 TO 45 INCHES OF
SNOW. THIS DROPPED DOWN TO 25 TO 35 INCHES AS ONE HEADED SOUTH
THROUGH THE CENTRAL HIGHLANDS. AREAS ALONG AND SOUTH OF THE 1-95
CORRIDOR GENERALLY HAD 1 TO 2 FEET OF SNOW ON THE GROUND, WHILE
COASTAL AREAS HAD 1 FOOT OR LESS. THIS IS ALL ABOVE NORMAL FOR THE
LATTER HALF OF MARCH, THOUGH COASTAL AREAS ARE LIKELY NEAR NORMAL.

THE SNOW WATER EQUIVALENT, OR THE AMOUNT OF WATER CONTAINED IN THE
SNOWPACK, IS ALSO ABOVE NORMAL OVER A VAST MAJORITY OF THE REGION.
VIRTUALLY ALL OF OUR FORECAST AREA REPORTED 6 TO 9 INCHES OF WATER IN
THE SNOWPACK, WITH DOWNEAST AREAS MORE LIKE 4 TO 7 INCHES. SOME OF
THE HIGHER ELEVATIONS IN THE CENTRAL HIGHLANDS BACK INTO THE BIG
WOODS ARE REPORTING AROUND 10 INCHES OF SWE. THIS IS ABOVE NORMAL
FOR THE REGION. AGAIN, THE EXCEPTION IS THE IMMEDIATE COAST, WHERE
THE SNOW WATER EQUIVALENT IS LIKELY CLOSE TO NORMAL.

...SOIL MOISTURE AND WATER SUPPLY CONDITIONS...

GIVEN THE COLD WEATHER AND LIMITED RUNOFF WE'VE EXPERIENCED OVER
THE PAST COUPLE OF MONTHS, SOIL MOISTURE STATES HAVE CONTINUED TO
DRY OUT ACROSS THE REGION. AS A RESULT, NEAR SURFACE SOIL MOISTURE
STATES ARE RUNNING NEAR NORMAL ACROSS MUCH OF THE REGION. THE
EXCEPTION IS EASTERN AROOSTOOK AND WASHINGTON COUNTIES WHICH ARE
STILL SHOWING SOIL MOISTURE STATES THAT ARE A BIT WETTER THAN
NORMAL. THE LATEST PALMER DROUGHT SEVERITY INDEX, WHICH LOOKS AT
MOISTURE STATES ON A LONGER TIME SCALE, SHOWED MUCH OF THE REGION
WITH NEAR NORMAL CONDITIONS.

...RIVER AND ICE CONDITIONS...

AREA RIVERS HAVE CONTINUED TO HOLD FAIRLY STEADY OVER THE PAST
SEVERAL DAYS. WE'RE STARTING TO SEE SOME SLIGHT RISES IN OUR
DOWNEAST RIVERS FROM TODAY'S RAINFALL, BUT THESE AREN'T EXPECTED
TO AMOUNT TO MUCH AS THE PRECIPITATION HAS PRETTY MUCH ENDED.
OTHERWISE, RIVER FLOWS ARE ACTUALLY RUNNING BELOW NORMAL FOR THIS
TIME OF YEAR DUE TO THE LIMITED AMOUNT OF RUNOFF WE'VE HAD. WHERE
THERE IS DEEP SNOW (WHICH IS JUST ABOUT EVERYWHERE), RIVER FLOWS
WILL INCREASE DRAMATICALLY ONCE THE SNOW MELT SEASON BEGINS IN
EARNEST. THIS WILL LIKELY NOT BE UNTIL EARLY APRIL.

RIVER ICE IS VERY WIDESPREAD AND THICK ACROSS THE NORTHERN RIVERS.
THICKNESSES AROUND 2 FEET ARE COMMON ALONG THE SAINT JOHN,
ALLAGASH, AND AROOSTOOK RIVERS, WITH UP TO 3 FEET POSSIBLE IN THE
UPPER REACHES. CENTRAL RIVERS ARE LIKELY COVERED WITH ICE THAT IS
AROUND 15 TO 25 INCHES THICK. THESE ARE GENERALLY NEAR TO A BIT
ABOVE NORMAL. FOR THOSE STRETCHES THAT BROKE UP IN JANUARY, THE ICE HAS
ONLY GROWN TO 12 TO 18 INCHES THICK. OUR DOWNEAST WATERWAYS
GENERALLY HAVE ICE THAT IS 1 FOOT OR LESS IN THICKNESS. THIS IS
NEAR TO A BIT BELOW NORMAL FOR THIS PART OF THE SEASON.

SEVERAL JAMS REMAIN LOCKED IN PLACE ACROSS CARIBOU'S FORECAST
AREA. THESE INCLUDE BUT ARE NOT LIMITED TO ICE JAMS ON THE SAINT
JOHN UPSTREAM OF FORT KENT, THE EAST BRANCH OF THE PENOBSCOT RIVER
DOWNSTREAM OF GRINDSTONE, THE PENOBSCOT RIVER NEAR WINN, THE
PISCATAQUIS RIVER UPSTREAM OF HOWLAND, AND THE KENDUSKEAG STREAM
IN DOWNTOWN BANGOR. IT SHOULD BE NOTED THAT WE RECEIVED
INFORMATION FROM A MEMBER OF THE PUBLIC EARLIER THIS WEEK THAT THE
JAM ON THE SAINT JOHN IS POSSIBLY SEVERAL MILES LONG. THE JAM ON
THE PISCATAQUIS IS ALSO QUITE LARGE AT NEARLY A MILE LONG. ALL OF
THESE JAMS ARE STILL WELL FROZEN IN PLACE AND ARE NOT EXPECTED TO
MOVE OVER THE NEXT COUPLE OF WEEKS. HOWEVER, SHOULD A PROLONGED
WARM UP OCCUR, ESPECIALLY ACCOMPANIED BY SIGNIFICANT RAINFALL,
THESE EXISTING JAMS WILL LIKELY SERVE AS A FOCUS FOR ADDITIONAL
JAMMING AND POTENTIAL FLOODING. IN ADDITION, THE ICE ALONG THE
UNBROKEN STRETCHES IS VERY WELL ESTABLISHED AND WHILE IT WILL TAKE
MAJOR RIVER RISES TO BREAK IT UP, IT WILL BE MORE SUSCEPTIBLE TO
CAUSING JAMMING ONCE IT DOES RELEASE.

...IN CONCLUSION...

BASED ON THE AFOREMENTIONED INFORMATION, THE WINTER/SPRING FLOOD
POTENTIAL IS ABOVE NORMAL ACROSS MOST OF OUR FORECAST AREA. THE
EXCEPTION IS ALONG THE COAST WHICH IS CLOSER TO NORMAL OWING TO
LESS SNOWPACK. ALTHOUGH RIVER FLOWS AND GROUNDWATER LEVELS ARE
GENERALLY BELOW NORMAL AND SOIL MOISTURE STATES ARE NEAR TO JUST
ABOVE NORMAL, SNOW DEPTHS AND THE AMOUNT OF WATER CONTAINED IN
THE PACK ARE BOTH RUNNING NEAR OR ABOVE NORMAL FOR LATE MARCH.
WITH COLD WEATHER EXPECTED TO LINGER THROUGH THE REST OF THIS
MONTH, IT IS LIKELY THAT WE WILL HEAD INTO SPRING WITH A DEEPER
THAN NORMAL AND WATER-LADEN SNOWPACK. THIS MEANS WE'LL HAVE
INCREASED CHANCES FOR FLOODING ONCE THE MELT PERIOD GETS
UNDERWAY. IT IS IMPORTANT TO STRESS THAT THIS POTENTIAL IS IN THE
LONGER TERM AND DOES NOT APPLY OVER THE NEXT WEEK OR SO.

THE POTENTIAL FOR FLOODING DUE TO ICE JAMS IS ABOVE NORMAL ACROSS
THE REGION. AGAIN, THE EXCEPTION LIES ALONG THE COAST WHERE
WATERWAYS GENERALLY HAVE NEAR TO BELOW NORMAL ICE COVER. AWAY
FROM THE COAST, ICE THICKNESSES ARE 15 TO 25 INCHES IN CENTRAL
WATERWAYS WHILE NORTHERN RIVERS ARE COVERED WITH ICE THAT IS 2 TO
3 FEET THICK. ALL INDICATIONS ARE THAT THE ICE IN THESE AREAS,
ESPECIALLY ALONG THE NORTHERN RIVERS, HAS A LOT OF STRUCTURAL
INTEGRITY. ALTHOUGH LITTLE TO NO ADDITIONAL RIVER ICE GROWTH IS
EXPECTED FROM HERE ON THROUGH SPRING, THE ICE WILL LIKELY REMAIN
INTACT UNTIL FLOWS INCREASE FROM SNOWMELT AND/OR A HEAVY RAIN
EVENT. THIS WILL LIKELY NOT OCCUR PRIOR TO EARLY APRIL. FOR
CENTRAL AND SOUTHERN WATERWAYS, SEVERAL ICE JAMS ARE WELL LOCKED
INTO PLACE AND COULD VERY WELL SERVE AS FOCUS POINTS FOR
ADDITIONAL JAMMING AND POTENTIAL FLOODING. WITH ALL THIS IN MIND,
THERE IS A HIGHER THAN NORMAL LIKELIHOOD FOR ICE JAM PROBLEMS
ACROSS THE REGION THIS SPRING.

IT IS IMPORTANT TO REMEMBER THAT VERY HEAVY RAINFALL CAN BRING
FLOODING AT ANY TIME OF THE YEAR, EVEN IN AREAS THAT HAVE LITTLE
OR NO SNOW ON THE GROUND.

THE NEXT WINTER/SPRING FLOOD POTENTIAL OUTLOOK WILL BE ISSUED BY
NWS CARIBOU ON THURSDAY, APRIL 3, 2014.

$$

HASTINGS