Public Information Statement
Issued by NWS Portland, ME

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MEZ007>009-012>014-018>022-023>028-NHZ001>010-013-014-191200

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE GRAY ME
950 AM EST WED MAR 18 2015

THE NATIONAL WEATHER SERVICE HAS DECLARED THE WEEK OF MARCH
15TH THROUGH 21ST FLOOD AWARENESS WEEK IN MAINE AND NEW
HAMPSHIRE, AS WELL AS THE REMAINDER OF THE UNITED STATES.

...DETERMINING THIS YEAR`S CURRENT CONDITIONS AND FLOOD POTENTIAL...

TO HELP DETERMINE THE POTENTIAL FOR FLOODING, THE NATIONAL
WEATHER SERVICE OFFICES THAT SERVE NORTHERN NEW ENGLAND
CONTINUALLY MONITOR HYDROLOGICAL CONDITIONS THROUGHOUT THE
REGION.  RIVER STATEMENTS ARE ISSUED DAILY AND CONTAIN
FORECASTS OF THE WATER LEVELS FOR THE MAJOR RIVERS IN THE
AREA.  ALSO, DURING THE LATE WINTER AND EARLY SPRING THE
NATIONAL WEATHER SERVICE, IN COORDINATION WITH OTHER FEDERAL
AND STATE AGENCIES, POWER COMPANIES, AND COOPERATIVE
OBSERVERS, SURVEYS THE SNOW PACK ACROSS THE AREA TO
DETERMINE THE POTENTIAL FOR SPRING FLOODING.

THERE ARE SEVERAL FACTORS THAT CONTRIBUTE TO THE SPRING
FLOOD POTENTIAL.  THESE INCLUDE THE AMOUNT OF SNOW ON THE
GROUND, THE AMOUNT OF WATER CONTAINED IN THE SNOW (OFTEN
REFERRED TO AS WATER EQUIVALENT OR WATER CONTENT), THE
DENSITY OF THE SNOWPACK, AND CURRENT RIVER AND STREAM
LEVELS.  THE WATER EQUIVALENT OF THE SNOWPACK REPRESENTS THE
WATER THAT WILL BE RELEASED AS THE SNOW MELTS.  THE DENSITY
OF THE SNOW IS AN INDICATION OF WHETHER ANY MELTED SNOW (OR
SUBSEQUENT RAIN) CAN BE ABSORBED BY THE SNOWPACK, OR WILL BE
RELEASED.  ANOTHER FACTOR IS HOW FAST THE SNOW WILL MELT.
AS A GENERAL RULE, THE RATE OF MELTING IS RELATED TO THE
TEMPERATURE, HUMIDITY, AND WIND.  WARM TEMPERATURES
ACCOMPANIED BY HIGH HUMIDITY AND WIND CAUSE THE GREATEST
AMOUNT OF MELTING.   IN ADDITION, THE STATE OF THE SOIL
(FROZEN VERSUS THAWED AND SATURATED VERSUS UNSATURATED)
DETERMINES WHETHER ANY MELTING SNOW WILL BE ABSORBED BY THE
GROUND.  MOST IMPORTANTLY, HOWEVER, THE GREATEST
CONTRIBUTING FACTOR TO FLOOD POTENTIAL IS RAINFALL.  IN NEW
ENGLAND, MAJOR FLOODING DOES NOT OCCUR DUE SOLELY TO MELTING
SNOW.

IN ADDITION, FLOODING CAN OCCUR DUE TO ICE JAMS.  ICE JAMS
TEND TO OCCUR IN THE SPRING WHEN WATER LEVELS ON RIVERS
START TO RISE AND WHEN THERE IS STILL A SIGNIFICANTLY THICK
LAYER OF ICE ON THE RIVERS.  THE RISING WATER IN RIVERS
CAUSES THE ICE TO BREAK UP, ALLOWING LARGE CHUNKS OF ICE TO
START FLOWING.  THESE CHUNKS OF ICE CAN JAM AS THEY FLOW
DOWNSTREAM.  THE JAMMED ICE CAN THEN ACT AS A DAM AND CAN
PREVENT WATER AND ICE FROM FLOWING DOWNSTREAM.  ICE JAMS ARE
UNPREDICTABLE AND WATER BEHIND ICE JAMS CAN RISE VERY
QUICKLY.  IN ADDITION, WHEN AN ICE JAM BREAKS UP, THE
RESULTING RELEASE CAN FLOOD DOWNSTREAM AREAS VERY RAPIDLY.

PLEASE NOTE THAT THE FOLLOWING INFORMATION ON CURRENT
CONDITIONS IS BASED ON SNOW SURVEYS TAKEN MARCH 10TH AND
11TH.  PLEASE REFER TO THE FOLLOWING WEB SITE (IN LOWER
CASE) FOR THE LATEST SNOW CONDITIONS IN MAINE AND PORTIONS
OF NEW HAMPSHIRE

HTTP://WWW.MAINE.GOV/MEMA/WEATHER/SNOW.HTM

THE FOLLOWING WEB SITE (IN LOWER CASE) PROVIDES UP-TO-DATE
RIVER AND FLOOD INFORMATION.

HTTP://WEATHER.GOV/NERFC

THE FOLLOWING WEB SITE PROVIDES INFORMATION ON ICE JAMS.

HTTP://ICEJAMS.CRREL.USACE.ARMY.MIL/


CURRENT CONDITIONS:

.CURRENT SNOW DEPTH AND WATER EQUIVALENT...SNOW DEPTHS
ACROSS WESTERN MAINE AND NEW HAMPSHIRE RANGE FROM 12 TO 24
INCHES IN SOUTHERN AND COASTAL AREAS TO 18 TO 36 INCHES IN
THE MOUNTAINS OF NORTHERN NEW HAMPSHIRE AND WESTERN MAINE
WITH LOCALLY HIGHER AMOUNTS.  THE WATER EQUIVALENT OF THE
SNOWPACK RANGES FROM 5 TO 7 INCHES IN THE SOUTH AND ALONG
THE COAST TO 6 TO 9 INCHES WITH LOCALLY HIGHER AMOUNTS IN
THE MOUNTAINS.  THESE VALUES ARE NEAR TO ABOVE NORMAL FOR
THIS TIME OF YEAR.

.CURRENT SNOW DENSITY...THE DENSITY OF THE SNOWPACK
GENERALLY RANGES FROM ABOUT .20 IN THE MOUNTAINS TO ABOUT
.30 ALONG THE COAST.  A SNOW PACK WITH A DENSITY OF AT OR ABOVE .40
IS CONSIDERED "RIPE" BECAUSE IT WILL HOLD NO MORE WATER AND ANY
RAINFALL OR MELTING WITH RESULT IN RUNOFF.

.CURRENT RIVER LEVELS...WATER LEVELS AND FLOWS IN RIVERS AND
STREAMS THROUGHOUT MAINE AND NEW HAMPSHIRE ARE GENERALLY
NEAR NORMAL FOR THIS TIME OF YEAR.

.FORECAST TEMPERATURES AND PRECIPITATION...
BELOW NORMAL TEMPERATURES ARE EXPECTED TO CONTINUE FOR THE
NEXT TWO WEEKS WITH NEAR NORMAL PRECIPITATION.  CURRENT
COMPUTER MODEL FORECASTS DO NOT SHOW ANY MAJOR STORMS
AFFECTING THE AREA DURING THE NEXT WEEK.  THE CONTINUING
COLD TEMPERATURES WILL LIMIT THE SNOW MELT DURING THE NEXT
TWO WEEKS.  ALTHOUGH THESE LOWER TEMPERATURES REDUCE THE
CHANCES FOR FLOODING DURING THE NEXT TWO WEEKS, THEY
INCREASE THE CHANCE FOR FLOODING LATER IN THE SEASON WHEN
STORMS TEND TO BE WARMER AND PRODUCE MORE RAINFALL.

.RIVER ICE AND ICE JAM POTENTIAL... ICE THICKNESSES ARE NEAR
NORMAL FOR THIS TIME OF YEAR.  THESE CONDITIONS, ALONG WITH
THE CONTINUED COLD TEMPERATURES EXPECTED DURING THE NEXT 10
DAYS, RAISES THE RISK FOR ICE JAM FLOODING LATER THIS
SPRING.

.FLOOD POTENTIAL OUTLOOK...THE OVERALL SPRING FLOOD
POTENTIAL ACROSS MAINE AND NEW HAMPSHIRE IS NEAR NORMAL IN
THE NEXT TWO WEEKS.  BEYOND THE NEXT TWO WEEKS, THE FLOOD
POTENTIAL IS ABOVE NORMAL. THE GREATEST CONCERN IS THAT, AS
WE GET LATER IN THE SEASON, THE CHANCE FOR THE COMBINATION
OF WARM TEMPERATURES, HEAVY RAINFALL, AND A RAPID SNOWMELT
INCREASES.

FLOODING IS THE TOP STORM-RELATED KILLER IN THE UNITED
STATES.  MANY FATALITIES OCCUR BECAUSE PEOPLE ATTEMPT TO
DRIVE THROUGH FLOODED ROADWAYS.  REMEMBER, IF YOU ENCOUNTER
A FLOODED ROAD, TURN AROUND, DON`T DROWN!

$$


JENSENIUS/HAWLEY
NATIONAL WEATHER SERVICE
GRAY, MAINE

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