Winter Isn't Over Yet, Spring Flooding Possible

Mar 11, 2014

   

Portion of GOES Eastern US SECTOR Infrared Image showing large mass heading towards Michigan
Portion of GOES Eastern US SECTOR Infrared Image showing large mass heading towards Michigan
Credit NOAA
 Another round of winter weather is expected to drop 3 to 7 inches of snow on southern Michigan, including the Washtenaw County area.  This could lead to Ann Arbor breaking the annual snowfall record.

 The National Weather Service issued winter storm watches ahead of the snow, which was expected to start Tuesday night and continue Wednesday. At its peak, the weather service says snow is expected to accumulate as quickly as an inch per hour.  The watch is currently in effect from 12:00AM to 8:00PM Wednesday.   From the National Weather Service

 

...WINTER STORM WATCH NOW IN EFFECT FROM LATE TONIGHT THROUGHWEDNESDAY EVENING... THE WINTER STORM WATCH IS NOW IN EFFECT FROM LATE TONIGHT THROUGHWEDNESDAY EVENING. HAZARDOUS WEATHER...  
  •  RAIN WILL TRANSITION TO ALL SNOW TUESDAY NIGHT. THE SNOW WILL CONTINUE INTO WEDNESDAY EVENING AND MAY BE HEAVY AT TIMES WEDNESDAY MORNING...POSSIBLY ACCUMULATING AT RATES OF AN INCH PER HOUR. TOTAL SNOWFALL OF AROUND 6+ INCHES IS POSSIBLE. THE HIGHEST ACCUMULATIONS ARE EXPECTED SOUTH OF A LINE FROM ANN ARBOR TO PONTIAC TO PORT HURON.
  •  WINDS WILL TURN TO THE NORTH TUESDAY NIGHT AND INCREASE DURING THE DAY WEDNESDAY. NORTHERLY WIND GUSTS OVER 30 MPH ARE POSSIBLE WEDNESDAY...WHICH COULD CAUSE SOME BLOWING AND DRIFTING OF THE SNOW.
  • TEMPERATURES WILL FALL THROUGH THE 20S ON WEDNESDAY...WHILE WIND CHILL READINGS DROP INTO THE SINGLE DIGITS.

 IMPACTS... 

  •  ROADS MAY BECOME SNOW COVERED AND VERY SLIPPERY.
  • VISIBILITIES WILL BECOME POOR DUE TO BOTH FALLING AND BLOWING SNOW.

PRECAUTIONARY/PREPAREDNESS ACTIONS... 

  •  A WINTER STORM WATCH MEANS THERE IS A POTENTIAL FOR SIGNIFICANT SNOW THAT MAY IMPACT TRAVEL. CONTINUE TO MONITOR THE LATEST FORECASTS.
  • PREPARE...PLAN...AND STAY INFORMED. VISIT HTTP://GO.USA.GOV/RR8

     The most snow is expected in the south of Washtenaw County near Ohio and Indiana.

  Rain may fall ahead of the snow in places, leaving roads icy. Temperatures will drop through the 20s on Wednesday, with wind chill readings in the single digits. Winds gusting to more than 30 mph on Wednesday also are predicted to hamper visibility.

    Additionally, The National Weather Service has implemented protocols to keep a close eye on area rivers which have a much higher risk than normal of flooding this year.  From their Hydrologic Outlook table the Huron River, which historically has a less than 5% chance of major or moderate flooding in Ann Arbor, this year has a 12% chance of moderate flooding and 35% chance of major flooding.  In Hamburg, the Huron River has more than a 95% chance of minor flooding.  In Dexter, Mill Creek is at its highest level in years and has a better than 41% chance of major flooding this spring.  According to the National Weather Service, the following dangers also exist:

THE FURTHER INTO SPRING THE SNOW PACK AND HIGH WATER CONTENT REMAIN...

THE HIGHER CHANCE FOR A QUICKER MORE SIGNIFICANT THAW. WITH THE MUCHABOVE AVERAGE SNOW PACK AND WATER CONTENT ALONG WITH MUCH DEEPER THENAVERAGE FROST DEPTH...ALL RIVERS ACROSS SOUTHEAST MICHIGAN HAVE A HIGHPROBABILITY OF AT LEAST MINOR FLOODING THIS SPRING.  THE RIVER BASINSTHAT HAVE THE HIGHEST CONTENT OF WATER STORED IN THE SNOW PACK AND THEHIGHEST PROBABILITY OF MODERATE TO MAJOR FLOODING ARE THE CASS...SHIAWASSEE...SAGINAW...CLINTON...HURON AND RAISIN.  THE OTHER THREAT THAT IS ALSO HIGH IS FOR ICE JAMS.  ALL THE RIVERSARE MOSTLY ICE COVERED AND THE ICE IS UNUSUALLY THICK.  BREAK UP OFRIVER ICE...ESPECIALLY DUE TO RAPID RISE AND INCREASE FLOW IN ARIVER CAN LEAD TO SERIOUS ICE JAMS AND THE POSSIBILITY OF FLASHFLOODING IMMEDIATELY BEHIND THE JAM OR DOWNSTREAM IF AN ICE JAMGIVES WAY ABRUPTLY.  ONE CAN TELL IF AN ICE JAM IS NEARBY IF THEYOBSERVE UNUSUAL RAPID RISE OR FALL IN A RIVER.  A RAPID FALL WOULDINDICATE A JAM UPSTREAM AND RAPID RISE A JAM DOWNSTREAM OR VICEVERSA IF A JAM GIVES AWAY.