Boston Blizzard: How it Melts Matters as Much as How Much Falls

February 13, 2015 Updated: July 18, 2015

As Boston braces for more heavy snow in an unusually snowy winter, the forecasts are all about how much snow will fall, but it might be more important to ask how it’s going to melt.

According to a water expert, warm rain after a large snowfall and freezing temperatures is the worst formula.

With heavy snow, comes flooding. Just how severe the flooding can become depends on whether we have dry days or rainy days after the snow.

Jerry Butch, a hydrologist with the U.S. Geological Survey, said the quantity of water in the snow is a factor in determining whether or not rivers will flood.

“The key is how quickly it melts to determine how quickly that water in the snow flows into the rivers, how quickly and how much they rise,” he said.

He says that melting caused by a very heavy rain and above normal temperatures is most detrimental. “If a nor’easter with a rainstorm happens, that would be the worse case. A warm rain is worse than sun melt over days,” Butch added.

Warm, dry days are best after a large snowfall because the snow melts slower over a period of days, which means less water flowing into the rivers at once.