NORTHERN MICHIGAN -- Although it seems like a a long way off yet, the start of spring is now less than a month away, and with that, the thoughts turn to snowmelt and its impact on flooding along area rivers, etc... which tends to occur at least in some places in the spring months. 

The National Weather Service has released the annual spring flood potential outlook which takes into account a few different factors such as the depth of the snowpack, how much water is locked up in the snow (water equivalency) river ice, and the spring climate outlook. Flooding could quickly get out of control if a rapid spring warmup occurs which is always the fly in the ointment as happened in western Upper Michigan in the spring of 2002. I have added some of the information below. The 7&4 Storm Team will update this and continue to monitor the snowpack across the north of Michigan. -Meteorologist Joe Charlevoix

***SOURCE: NWS GAYLORD AND GRAND RAPIDS

...LOW TO MODERATE THREAT FOR SPRING FLOODING ACROSS NORTHERN MICHIGAN...

THE SPRING 2008 FLOOD OUTLOOK FOR NORTHERN MICHIGAN INDICATES A LOW
PROBABILITY OF FLOODING DUE TO SNOWMELT WITHIN THE PINE...AU SABLE...
MANISTEE...AND BOARDMAN RIVER BASINS...WITH A MODERATE PROBABILITY OF
FLOODING IN THE RIFLE RIVER BASIN.

THIS OUTLOOK COVERS CHIPPEWA AND MACKINAC COUNTIES IN EASTERN UPPER
MICHIGAN...WHICH INCLUDES THE PINE RIVER BASIN...AND THE NORTHERN HALF
OF LOWER MICHIGAN...WHICH ENCOMPASSES THE MANISTEE...THUNDER BAY...AU
SABLE...CHEBOYGAN...BOARDMAN...AND RIFLE RIVER BASINS.

IN THE TABLE BELOW...THE 90 THROUGH 10 PERCENT COLUMNS INDICATE THE
CHANCE THE RIVER COULD RISE ABOVE THE LISTED STAGE LEVELS IN THE NEXT
90 DAYS.
       
CHANCE OF EXCEEDING STAGES AT SPECIFIC LOCATIONS
          VALID FEBRUARY 25, 2008 - MAY 25, 2008

LOCATION          FS     90%  80%  70%  60%  50%  40%  30%  20%  10%
--------         ----    ---  ---  ---  ---  ---  ---  ---  ---  ---
BOARDMAN RIVER
  MAYFIELD        7.0    4.1  4.1  4.2  4.3  4.4  4.5  4.7  4.8  5.1
MANISTEE RIVER
  SHERMAN        15.0   13.4 13.6 13.9 14.0 14.2 14.5 14.8 15.3 15.7
AU SABLE RIVER
  RED OAK         7.0    4.8  5.1  5.3  5.4  5.7  5.7  5.9  6.2  6.6
RIFLE RIVER
  STERLING        6.0    5.2  5.5  5.9  6.3  6.8  7.1  7.6  8.7  9.4
PINE RIVER
  RUDYARD        17.0    6.4  6.8  7.2  8.0  8.4  8.8  9.7 10.8 12.4

LOCATION         FS(FT)  APPROXIMATE PERCENT CHANCE OF FLOODING
MINOR MODERATE MAJOR DEP FROM NORMAL
--------         ------  -----  --------  -----  ---------------
MUSKEGON RIVER
EVART            12.0   20      < 5     < 5     5 % GREATER
CROTON            9.0   40      < 5     < 5     5 % GREATER
LITTLE MUSKEGON RIVER
MORLEY            6.0   < 10    < 5     < 5     5 % GREATER
WHITE RIVER
WHITEHALL         6.0   50      < 5     < 5     25 % GREATER
PERE MARQUETTE RIVER
SCOTTVILLE        5.5   10      < 5     < 5     5 % GREATER
CHIPPEWA RIVER
MT PLEASANT       8.0   30      < 5     < 5     30 % GREATER

CURRENT FORECASTS SUGGEST PROBABILITIES OF EXCEEDING FLOOD STAGE ON
THE BOARDMAN RIVER NEAR MAYFIELD...THE PINE RIVER NEAR RUDYARD...
AND THE AU SABLE RIVER NEAR RED OAK...ARE LESS THAN 10 PERCENT
THROUGH THE END OF MAY.  PROBABILITY OF EXCEEDING FLOOD STAGE ON
THE MANISTEE RIVER NEAR SHERMAN IS AROUND 20 PERCENT...WHILE THE
PROBABILITY OF FLOODING ON THE RIFLE RIVER NEAR STERLING IS AROUND
60 PERCENT.

IN THE TABLE BELOW...THE 10 THROUGH 90 PERCENT COLUMNS INDICATE THE
CHANCE THE RIVER COULD FALL BELOW THE LISTED STAGE LEVELS IN THE NEXT
90 DAYS.

      CHANCE OF FALLING BELOW STAGES AT SPECIFIC LOCATIONS
          VALID FEBRUARY 25, 2008 - MAY 25, 2008

LOCATION          FS     10%  20%  30%  40%  50%  60%  70%  80%  90%
--------         ----    ---  ---  ---  ---  ---  ---  ---  ---  ---
BOARDMAN RIVER
  MAYFIELD        7.0    3.1  3.1  3.1  3.1  3.2  3.2  3.2  3.2  3.2
MANISTEE RIVER
  SHERMAN        15.0   11.4 11.5 11.5 11.6 11.6 11.7 11.7 11.7 11.7
AU SABLE RIVER
  RED OAK         7.0    2.7  2.8  2.8  2.8  2.8  2.8  2.9  2.9  2.9
RIFLE RIVER
  STERLING        6.0    1.5  1.5  1.6  1.6  1.6  1.6  1.6  1.7  1.7
PINE RIVER
  RUDYARD        17.0    1.9  1.9  1.9  1.9  1.9  1.9  2.0  2.0  2.0

...CURRENT CONDITIONS...

PRECIPITATION ACROSS NORTHERN MICHIGAN DURING THE FALL SEASON
(SEPTEMBER THROUGH NOVEMBER) VARIED FROM SOUTH TO NORTH ACROSS
NORTHERN MICHIGAN.  PRECIPITATION AVERAGED AROUND 50 PERCENT OF
NORMAL SOUTH OF M-72 (WITHIN THE BOARDMAN...AU SABLE...MANISTEE...
AND RIFLE RIVER BASINS)...INCREASING TO NEARLY 150 PERCENT OF
NORMAL ACROSS EASTERN UPPER MICHIGAN (AFTER A SUMMER OF MODERATE
TO SEVERE DROUGHT CONDITIONS).  FOR THE WINTER SEASON THUS FAR
(DECEMBER THROUGH LATE FEBRUARY)...PRECIPITATION HAS BEEN RUNNING
FROM NEAR 100 TO 150 PERCENT OF NORMAL.  SNOWFALL HAS BEEN
UNUSUALLY HEAVY ACROSS PORTIONS OF NORTHWEST LOWER MICHIGAN
WEST OF US-131 AND SOUTH OF M-72...AREAS THAT ARE OUTSIDE OF THE
MORE TYPICAL LAKE EFFECT SNOW BELTS.  SNOW DEPTHS ACROSS EASTERN
UPPER AND MUCH OF NORTHWEST LOWER MICHIGAN...INCLUDING THE PINE...
CHEBOYGAN...BOARDMAN...AND MANISTEE RIVER BASINS...RANGED FROM 15 TO
25 INCHES IN THIS AREA...WITH SNOW WATER EQUIVALENTS OF 3 TO 6
INCHES. ACROSS MUCH OF THE AU SABLE AND RIFLE RIVER BASINS...SNOW
DEPTH RANGES FROM 4 TO 8 INCHES ON AVERAGE...WITH SNOW WATER
EQUIVALENT FROM 1 TO 4 INCHES.

SOIL MOISTURE TO A DEPTH OF 12 INCHES WAS ABOVE NORMAL ACROSS ALL
OF NORTHERN LOWER AND EASTERN UPPER MICHIGAN.  FROST DEPTHS WERE
GENERALLY ONE FOOT OR LESS.

STEAMFLOW CONDITIONS ARE RUNNING NEAR NORMAL ON MOST NORTHERN
MICHIGAN RIVERS...WITH SOME FLUCTUATIONS DUE TO RECENT ICE JAM
ACTIVITY.