The deadly storm system could deliver severe heat to the East Coast and Midwest|@realmitchlittle|X

Severe storms and tornadoes have destroyed 200 buildings and structures in parts of Texas, Oklahoma, Arkansas and Kentucky, leaving at least 17 people dead and more than 100 injured over the Memorial Day weekend.

The deadly storm system continued to pose a threat to 15 million people residing between Indiana and Missouri. By late Sunday, there were 80,000 outages in Arkansas, 90,000 in Missouri, and 3,000 in Oklahoma.

It could also deliver severe heat to the East Coast and Midwest, with heat indices approaching 115 degrees.

Weather scientists say a persistent pattern of warm, moist air is the reason behind the string of tornadoes in the past two months. The National Weather Service says April saw around 300 tornadoes, the second most on record.