Ice Jam Flood Threat Continues; JRWeather Flood Watch In Effect

Local Update...
   Moderate To Heavy Rain Moving Into Northern New York; JRWeather Flood Watch Remains In Effect Until 8PM Thursday...

JRWeather FLOOD WATCH
     JRWeather Continues A Flood Watch for all of Northern New York, and All of Vermont except Grand Isle County From Until 8PM Thursday.

     Unseasonably warm temperatures, and rain will continue, leading to the potential of Ice Jam Flooding from this evening into Thursday evening.

     Temperatures reached the low 50'sF in a few places today, with widespread mid to upper 40's across the region. Thursday temperatures are going to be in the mid 40'sF and slowly fall throughout the day. These above freezing temperatures and resultant snow melt combined with rainfall amounts of a half to three quarters of an inch into Thursday afternoon, will result in rapid rises on area rivers into Thursday. River ice is quite thick at this time, so the threat for ice jam flooding is relatively high, as the river levels rise.

     Of most concern is where any ice jams formed earlier this winter, and then froze in place. These areas will be the largest focus for ice jam flooding. The highest risk areas for ice jam flooding at this time are the Missisquoi River near East Highgate, Berkshire, Enosburgh, and Swanton, The Great Chazy River near Perry Mills, The East Branch of the Ausable River near Ausable Forks, The Winooski River near Montpelier, and The Lamoille River near Johnson, and Cambridge. These areas are where previous ice jams had formed and froze in place earlier this winter.

     Temperatures should fall below freezing Thursday evening, reducing runoff and ending and additional ice jam threat. A Flood watch is issued when there is the potential for flooding to occur, but not imminent. In this case the potential for ice jam flooding exists. If you live in an area prone to Ice Jam flooding then monitor the nearby waterway closely. At any sign of flooding move immediately to higher ground. Stay tuned for further updates.


DISCUSSION
     As of this time area rivers are behaving, but how well they will continue to behave is in question. Area rivers are just starting to show signs of rising. What happens through the overnight hours will be key as to how much ice jamming will occur. Rivers will need to rise atleast a couple more feet before the ice will severely break up.
     Rain moving into the region overnight will help aid in runoff and help raise river levels. At this point the heaviest rain is expected to be across Northern New York, where isolated areas of up to 1 inch of rain could fall. Widespread amounts though will be around a half to three quarters of an inch, and in Vermont amounts will range from a quarter to half inch. These amounts of rain in a 5-8 hour period of time, combined with snow melt will result in significant river rises, causing ice to break and jam up.
     The most significant threat areas are the East Branch of the Ausable River near Ausable Forks, and The Great Chazy River near Perry Mills, as these two rivers are expected to crest near action stage. This is not counting any ice jam potential at all. If the river rose to near action stage and jammed some significant flooding could occur. Other areas of special concern are the Missisquoi River near Berkshire, Enosburgh, and Highgate, The Otter Creek near Rutland, The Winooski River near Montpelier, The Lamoille River near Johnson, and Cambridge, and the Saranac River near Plattsburgh. These rivers are forecasted to have sharp rises but not near action stage like The Great Chazy, or The East Branch of the Ausable. Eitherway, the rivers where sharp rises occur will be the ones to Jam up.
     Other areas at a more moderate risk, rather then a high risk, are the Mississquoi River near North Troy, and Swanton, Lamoille River near Georgia, The Winooski River near Essex, The Otter Creek near Middlebury, and the Mad River in Moretown.
     If you live near area rivers, creeks, or streams, that are known to be vulnerable to ice jam flooding, then pay close attention to them. At the first sign of flooding move to higher ground.
     I will be unable to put out frequent Flood Warnings of my own, if they are needed, due to the fact I have to work, so stay tuned to the National Weather Service for official alerts, as well as your local media outlets.

Updated maps below...


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