Storms are lashing the East Coast from Virginia to Connecticut, flooding roadways and delaying flights from Boston to Washington, D.C.

A warmer atmosphere can hold more moisture, making storms capable of unleashing huge amounts of rain over land. Studies have shown that for every degree Fahrenheit that the planet heats up, the atmosphere can hold around 3% to 4% more moisture. As a result, flooding risks across the country are expected to increase in the coming years.

But as the heat lingered into the evening, the service began posting flood watches. By the afternoon of July 31, more than 50 million people in the region are forecast to be under a flood watch.