Why rare 'high risk' flood days need to be taken seriously
High risks are only issued on about 4% of days (including tropical and non-tropical events), but this risk category accounts for 39% of flood-related fatalities and 83% of flood-related damages in the continental U.S., according to research by meteorologists at NOAA's Weather Prediction Center.
Nearly all of Vermont under extreme risk of flash flooding
Several inches of rain could lead to catastrophic flash flooding in Vermont on Monday with impacts that haven't been seen in the state since Hurricane Irene in 2011.
Parts of Vermont were under a rare "high risk" of excessive rainfall on Monday, and it's important to take such a threat seriously because this magnitude of flooding can have destructive impacts.
NOAA's Weather Prediction Center (WPC) is the agency responsible for issuing daily excessive rainfall outlooks. The outlooks use four categories – marginal, slight, moderate and high – to indicate the probability of excessive rainfall leading to rapid-onset flooding within 25 miles of a point.
When a high risk – the highest risk level that can be issued – is in place, it means severe, widespread flash floods are expected in the highlighted areas.
"Areas that don't normally experience flash flooding, could," the WPC says. "Lives and property (are) in greater danger."
7 FACTS YOU SHOULD KNOW ABOUT FLASH FLOODS

NOAA's Weather Prediction Center is responsible for issuing daily excessive rainfall outlooks.
(NOAA / WPC)
High risks are only issued on about 4% of days (including tropical and non-tropical events), but this risk category accounts for 39% of flood-related fatalities and 83% of flood-related damages in the continental U.S., according to research by WPC meteorologists.
What's more, 46% of high-risk flood days have at least one fatality or injury, and 62% of such days have at least $1 million in damages, Greg Carbin, forecast operations branch chief at the WPC, noted in the research.

Statistics about high-risk flood days.
(NOAA / WPC)
Monday's high risk of excessive rainfall in Vermont was the first such risk issued for that state since August 2011 during Hurricane Irene.
"Expect significant to potentially catastrophic widespread flash flooding through Monday evening, with possible impacts not seen since (Hurricane) Irene," the National Weather Service office in Burlington, Vermont, wrote in a forecast discussion.
Irene produced a wide swath of 5 to 8 inches of rain across Vermont, which led to devastating mudslides and deadly flooding.
EXPLAINING FLOOD ALERTS ISSUED BY THE NATIONAL WEATHER SERVICE

Vermont was under a "high risk" of excessive rainfall Monday, July 10, 2023, for the first time since August 2011 during Hurricane Irene.
(FOX Weather)
This is not your typical flash-flood threat.
Your commute to work or school, the subway system, a parking lot, the street on which you live or even your home are all areas that could become inundated by floodwaters on a high-risk flood day. This can include areas that have never flooded in the past.
HERE'S WHAT TO DO AFTER YOUR CAR IS FLOODED
Many people underestimate the force and power of water.
"A mere 6 inches of fast-moving floodwater can knock over an adult," the National Weather Service says. "It takes just 12 inches of rushing water to carry away most cars, and just 2 feet of rushing water can carry away SUVs and trucks. It is NEVER safe to drive or walk into floodwaters."
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A car driving down an Oklahoma City road looked more like it was on a water ride after two days of flooding rain.
And remember: turn around, don't drown. Almost half of all flash-flood deaths happen in vehicles, according to FEMA.
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Be sure to pay close attention to your FOX Weather app and any government-issued alerts from the NWS that will warn you of life-threatening flooding at your location.