NWS: Ice jams pose short-notice flood threat

Photo of ice jam from NWS website.

HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1020 AM EST FRI JAN 17 2014

...WIDESPREAD ICE IMPACTING AREA RIVERS...

VERY COLD TEMPERATURES HAVE CAUSED ICE TO FORM ON NEARLY ALL RIVERS
ACROSS NORTHERN INDIANA...SOUTHWEST LOWER MICHIGAN AND FAR NORTHWEST
OHIO. RECENT WARMER TEMPERATURES AND RAINFALL CAUSED SOME SNOWMELT
WHICH IN TURN HAS CAUSED RIVERS TO RISE. AS THE RIVERS HAVE RISEN...
ICE HAS FRACTURED AND BEGUN FLOWING DOWNSTREAM. THIS CAN CAUSE
PROBLEMS IF THE ICE GETS STUCK CREATING A BUILD UP IN THE RIVER
/CALLED AN ICE JAM/. THE RIVER BEHIND THE JAM WILL BEGIN TO RISE
AND MAY CAUSE FLOODING. SHOULD THE JAM BREAK UP SUDDENLY...FLOODING
IS POSSIBLE DOWNSTREAM AS WATER IS RELEASED.

IT IS POSSIBLE THAT FLOODING WILL NOT BE DETECTED BY AREA RIVER
GAUGES. THEREFORE...FLOODING MAY OCCUR WITH LITTLE OR NO ADVANCE
WARNING.

RESIDENTS ALONG AREA WATERWAYS SHOULD REMAIN ALERT AND WATCH WATER
LEVELS TO DECIDE IF ANY ACTION IS REQUIRED. PLEASE REPORT ANY FLOODING
ASSOCIATED WITH ICE JAMS TO THE NATIONAL WEATHER SERVICE.

LISTEN TO NOAA WEATHER RADIO FOR FURTHER STATEMENTS AND FORECASTS AS
THIS FLOOD POTENTIAL DEVELOPS.