Flood Potential Outlook
Issued by NWS Burlington, VT

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11
000
FGUS71 KBTV 192155
ESFBTV
NYC019-031-033-089-VTC001-005-007-009-011-013-015-017-019-021-023-
027-212200-

WINTER/SPRING FLOOD POTENTIAL OUTLOOK
NATIONAL WEATHER SERVICE BURLINGTON VT
555 PM EDT THU MAR 19 2015

...INTERMEDIATE SPRING FLOOD POTENTIAL OUTLOOK /7/...

...LOW PROBABILITY OF SNOW MELT OR ICE JAM FLOODING THROUGH EARLY
APRIL...

THIS IS THE SEVENTH FLOOD OUTLOOK FOR THE 2015 WINTER/SPRING
SEASON. FLOOD OUTLOOKS ARE ISSUED BI-WEEKLY THROUGH THE WINTER AND
SPRING BY THE NATIONAL WEATHER SERVICE IN BURLINGTON VERMONT TO
SUMMARIZE THE FLOOD POTENTIAL DUE TO SNOW MELT AND BREAK UP OF
RIVER ICE ACROSS CENTRAL AND NORTHERN VERMONT, AND NORTHERN NEW
YORK.

...OVERVIEW...

THERE IS A LOW PROBABILITY FOR SNOW MELT OR ICE JAM FLOODING
THROUGH EARLY APRIL. THE SNOW PACK IS NEAR NORMAL AND RIVER ICE IS
THICK AND EXTENSIVE. FORECAST FOR BELOW NORMAL TEMPERATURES AND
LIGHT PRECIPITATION WILL KEEP SNOWMELT AND ICE JAM POTENTIAL LOW.
THE LONGER TERM SPRING MELT AND ICE JAM THREAT IS NEAR TO ABOVE
NORMAL.

...SNOW DEPTHS AND WATER EQUIVALENT...

A SHORT PERIOD OF ABOVE FREEZING DAYTIME TEMPERATURES EARLY IN
THE WEEK GENERATED SNOWMELT IN THE LOWER ELEVATIONS, AND SOME
RIPENING OF THE SNOWPACK IN HIGHER ELEVATIONS. OVERALL SNOW DEPTH
AND WATER EQUIVALENT REMAINS NEAR NORMAL FOR THIS TIME OF YEAR.

SNOW DEPTH IN NORTHERN NEW YORK RANGED FROM FOUR TO 12 INCHES IN
THE SAINT LAWRENCE VALLEY, AND ONE TO TWO FEET IN THE ADIRONDACKS.
IN THE HIGHEST TERRAIN MAINLY IN THE HIGH PEAKS REGION SNOW DEPTH
WAS THREE FEET OR MORE.

IN VERMONT, SNOW DEPTH RANGED FROM FIVE TO FIFTEEN INCHES BELOW
1500 FEET, AND ONE TO THREE FEET OVER HIGHER TERRAIN. IN THE
HIGHEST PEAKS SNOW DEPTH REMAINED FOUR FEET OR MORE.

THE CHAMPLAIN VALLEY OF NEW YORK AND VERMONT CONTINUED TO LOSE
SNOW COVERAGE EARLIER IN THE WEEK, WITH SNOW DEPTH DROPPING TO ONE
TO FOUR INCHES. SNOW WATER EQUIVALENT, OR THE LIQUID WATER CONTENT
HELD IN THE SNOWPACK, WAS AROUND ONE INCH.

IN THE SAINT LAWRENCE VALLEY AND NORTHERN SLOPES OF THE
ADIRONDACKS, SNOW WATER EQUIVALENT WAS TWO TO FOUR INCHES,
INCREASING TO FIVE TO SEVEN INCHES IN THE HIGH PEAKS. THIS IS
SLIGHTLY BELOW NORMAL TO NEAR NORMAL FOR THIS TIME OF YEAR. IN
VERMONT, INTERIOR VALLEYS HAD TWO TO FIVE INCHES, INCREASING TO
SIX TO NINE INCHES OVER THE HIGHER TERRAIN. THE HIGHEST PEAKS AND
MOUNTAIN PASSES HAD EIGHT TO 12 INCHES OF LIQUID. THE SNOW WATER
EQUIVALENT ACROSS VERMONT IS NEAR TO SLIGHTLY ABOVE NORMAL.

...RIVER AND SOIL CONDITIONS...

SNOWMELT FROM THE BRIEF PERIOD OF DAYTIME TEMPERATURES ABOVE
FREEZING THIS WEEK CAUSED VERY SMALL INCREASES IN RIVER FLOWS, BUT
REMAINED IN THE NORMAL RANGE. RIVER ICE CONTINUES TO SHOW THE
FIRST SIGNS OF MELT AS THE LAYER OF SNOW ON TOP OF RIVER ICE MELTS
AND ICE ALONG THE RIVER BANKS BEGAN TO DARKEN AND THAW. RIVER ICE
REMAINS EXTENSIVE AND THICK, WITH THE US GEOLOGICAL SURVEY
REPORTING RIVER ICE THICKNESS OF 1 TO 1.5 FOOT OF VERY HARD ICE ON
VERMONT AND NORTHERN NEW YORK RIVERS. THE INCREASING SUN AND
WARMING TEMPERATURES WILL CONTINUE THE ICE MELT PROCESS.

SOIL MOISTURE WAS NEAR NORMAL. THE THIN SNOW COVER AND FRIGID
TEMPERATURES HAVE ALLOWED FROST TO PENETRATE DEEP INTO THE SOIL,
WITH FROST DEPTHS DOWN TO 20 INCHES IN AREAS THAT HAD A LITTLE
SNOW COVER THROUGH JANUARY. AREAS THAT HAVE RETAINED SOME
INSULATING SNOW COVER REPORT FROST DEPTHS OF SEVEN TO TEN INCHES.
THE WARM TEMPERATURES THIS WEEK HAVE DONE LITTLE TO THAW THE
GROUND. FROZEN SOILS WOULD ENHANCE RUNOFF RATHER THAN ABSORB
EXCESS MOISTURE.

...WEATHER OUTLOOK...

LIGHT PRECIPITATION WITH ABOVE FREEZING TEMPERATURES FRIDAY AND
SATURDAY WILL BE REPLACED BY PLENTIFUL SUNSHINE EARLY NEXT WEEK
WITH COLDER TEMPERATURES. ANOTHER WARM UP EXPECTED FOR THE LATTER
HALF OF THE WEEK AHEAD OF ANOTHER SYSTEM WHICH WILL BRING
PRECIPITATION AND A RETURN TO COLDER WEATHER. THIS SEESAW OF
TEMPERATURES WILL CONTINUE INTO EARLY APRIL, BUT AVERAGE BELOW
NORMAL WITH TEMPERATURES ABOVE FREEZING DURING THE DAY AND BELOW
AT NIGHT. THIS SCENARIO IS FAVORABLE FOR A SLOW ORDERLY MELT OF
SNOW AND RIVER ICE.

...SUMMARY...

SNOW MELT OR ICE JAM FLOODING IS NOT FORECAST THROUGH EARLY
APRIL. SNOW WATER EQUIVALENT AMOUNTS NEAR NORMAL COMBINED WITH THE
COLD SNOWPACK AND FORECASTED COLD TEMPERATURES AND ONLY LIGHT
PRECIPITATION, A SLOW MELT OF SNOW AND RIVER ICE IS EXPECTED. THE
INCREASING SUN ANGLE WILL GRADUALLY RIPEN THE SNOWPACK AS WELL AS
FURTHER THE ICE MELTING PROCESS ON RIVERS. WEAKENING OF ICE ON
RIVERS, ESPECIALLY IN AREAS WHERE SNOW IS NOT COVERING THE ICE,
WILL BE GRADUAL. BUT OVERALL RIVER ICE COVERAGE IS WIDESPREAD AND
THICK AND WILL REMAIN LOCKED IN PLACE AS NO SIGNIFICANT RIVER
RISES ARE FORECAST.

THE PROBABILITY FOR LAKE CHAMPLAIN FLOODING IS LOW AS THE
SNOWPACK IS NEAR NORMAL AND SLOW SNOWMELT PROCESSES EXPECTED WITH
NO SIGNIFICANT PRECIPITATION EVENTS EXPECTED.

IT IS IMPORTANT TO NOTE THAT WHILE THE SLOW MELT IS WELCOME, IT
ALSO INCREASES THE RISK OF A LATER SEASON SIGNIFICANT WARMUP AND
HEAVY RAINFALL ON TOP OF THE LINGERING SNOW PACK.

THE NEXT WINTER/SPRING FLOOD OUTLOOK WILL BE ISSUED ON THURSDAY
APRIL 2.

ACCESS CURRENT WEATHER CONDITIONS AND FORECASTS ON OUR WEB SITE
AT WWW.ERH.NOAA.GOV/BTV.

$$

KGM


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.