Chart Shows Dramatic Change in Vermont River Water Levels as Dam Threatened

A chart of Winooski River water level changes shows the extreme flooding that is taking place in Montpelier, Vermont, fueling fears that a dam spillover may further flood the state's capital.

As of early Tuesday morning, the Wrightsville Dam in Montpelier only had 6 feet of storage remaining before the dam would exceed capacity. A spillover has never occurred before, meaning "there is no precedent for potential damage," according to a Facebook post from Montpelier city manager William Fraser.

Vermont was ravaged by a long-duration storm that hit the state on Monday after it moved through New York and caused severe flooding there on Sunday. Vermont battled rain all day Monday, with rain expected to continue through Tuesday. The intense storms destroyed some of the state's roads and sparked evacuations, and some residents were trapped in their homes.

On social media, people shared alarming photos of excessive flooding throughout Montpelier. The National Weather Service (NWS) Northeast River Forecast Center tweeted a chart that revealed the dramatic increase in water levels of the Winooski River. The Wrightsville Dam is located on the North Branch of the river.

Some areas of the state have received more than 9 inches of rain. Montpelier received 6.82 inches of rain, which surpassed Hurricane Irene levels from 2011.

At 6 a.m. ET on Monday, before much of the rain hit the state, storage levels at the dam were at approximately 7 feet. The flood stage occurs when levels reach 15 feet, which happened not even 12 hours later. Levels continued to rise quickly until they peaked at nearly 21 feet last night.

"After dropping slightly (only slightly!) overnight, the Winooski River at Montpelier is back on the rise just a bit this morning," NWS Northeast RFC tweeted on Tuesday morning. "Downstream at Essex Junction, water levels have yet to reach their peak."

The Winooski River isn't the only water that's rising in Montpelier. According to data from the United States Geological Survey, the Wrightsville Detention Reservoir rose by 25 feet over the course of the storm.

The NWS chart shows a forecast for the water levels, which meteorologists expect to fall nearly as quickly as they rose before returning to normal by Wednesday.

Rain was slowing on Tuesday, but AccuWeather meteorologist Alex DaSilva told Newsweek if rain continued to fall upstream of the dam, river levels could continue to rise despite the rain.

"We want to see those levels begin to drop," DaSilva said. "If something upstream happens, if there's another potential dam or anything upstream that could potentially release water, it could take those numbers up."

DaSilva said if another heavy band of rain passes through, the river could quickly rise the remaining 6 feet before dam spillover, that meteorologists aren't expecting any more rain in the area other than a light shower.