FOX44 - Burlington / Plattsburgh News, Weather & Sports10.27.11 Winter Weather Awareness- Flooding and Ice Jams

10.27.11 Winter Weather Awareness- Flooding and Ice Jams

Did you know? Flooding is the greatest natural hazard to the citizens, landscape, infrastructure, property, and economy for Vermont, northern New York. Did you know it can happen, not only in summer, but in winter too?

Frozen ice chunks that flow downstream can clog up, especially on river bends, which can lead to an ice jam and resultant flooding.   

A photo from Chenango Bridge, NY ice jam flooding of 2004. (above) Click link for more.

Flooding can occur at any time of the year, day or night.  There are 3 main sources for winter/cold season flooding...

1) Heavy rain on frozen ground

2) Melting of snow

3) Ice jams.

A combination of the three can also lead to flooding, which can be devastating. 

Generally, snowmelt along will cause rises on areas rivers and can cause minor lowland flooding on fields and roads. Snowmelt combined with heavy rain could cause more significant flooding. This scenario can commonly occur in late winter and early springtime, but has been known to happen in the dead of winter as it did in January of 1996.

Generally, ice jams occurs late winter to early spring as warmer temperatures accelerate snowmelt and ice melt on rivers. The ice eventually breaks-up, then flows in chunks, and can lead to a jam up along the river.  Ice jams tend to develop along bends in the rivers, along the intersection of rivers, or where this is an obstruction to the natural flow of water including man-made structures, such a bridges.  Major ice jams have led to major flooding in the past, In march 1992 along the Winooski River at Montpelier, and in March 2008 along the smaller waterway of the Dish Mill Brook in East.

Ice jams can also develop during the freeze up stage early in the season as ice forms within a river during spells of extremely cold temperatures.

In order to provide advanced notice of possible flood situations, the National Weather Service issues flood watches and warnings. Local media (me!) then relays that info to you as a viewer on our newscasts, social media (Facebook and Twitter), and website. A flood watch means that flooding is possible within the next 12-36 hours, and preparation should be made in case of flooding. A flood warning means that flooding is imminent or occurring, and immediate safety actions are necessary. To read more on how flood warnings/watches are issued, visit the National Weather Service full write up on Winter Weather Awareness week flooding, by clicking here.

Thanks for checking back AGAIN today for Winter Weather Awareness week, right here in our SkyTracker Weather Blogs. Enjoy the snowflakes out there today (or just cozy up inside and pretend it's not happening if you're not a fan)

Check back one last time for tomorrow's topic (and it's a bigtime important one to staying "in the know")- learn more about winter weather TERMINOLOGY. Do you know exactly what to expect when we say "a winter storm warning is in effect"? Or "there is a Winter Weather Advisory" for your town? No? Then you should check back tomorrow to make sure you are prepared for the cold & snowy winter ahead.