Winter Weather Awareness Week continues Thursday across the state of Pennsylvania. Each day, the National Weather Service chooses a topic to inform the public and help them prepare for what might be ahead.
Thursday’s topic is Winter Flooding.
A winter in Pennsylvania typically makes others think of snow, ice, and cold. Sometimes Mother Nature has other plans, and a mild winter season unfolds. Unseasonable warmth brings more rain, and more rain means more flooding potential.
Unseasonable warmth can act in many ways to cause flooding. It can quickly melt and snow pack, especially in the valleys. This saturates the ground and can swell the rivers. Sometimes, more rain moves in after this melting takes places, further increasing river levels. This could have increased impacts if snow packs cover grates and storm drains.
Weather systems, of course, can also bring hefty amounts of rainfall. One favorable storm track takes systems from the Ohio Valley northeast up the Saint Lawrence Valley into Canada. This track brings plenty of warm air from the Gulf of Mexico and plenty of moisture. Heavy rainfall often results.
Ice jams on the rivers can also cause winter flooding. River flows increase, and so do the water levels. This allows chunks of ice to float. Sometimes, large chunks of ice can pile up along a bend, island, or wide shallow area. The flow of the river can become blocked by the ice jam, and the river can overflow its banks. This can sometimes happen in less than an hour. As the water rises, the pressure can break the ice jam. The result is a sudden surge of water and ice flowing down the river. This can cause additional troubles downstream.
FOX43’s Weather Department will keep you informed as always this winter, so stay tuned throughout the winter. For more information on Winter Weather Awareness Week or the daily topics, head to the State College National Weather Service’s web page.
Stay safe this winter!