Almost 400k without power across southern U.S. amid dangerous heat wave

• A tornado hit part of southern Indiana on Sunday, killing at least one person in the state's Martin County.

Why it matters: Extreme heat, which is the top weather-related killer in the U.S., can be especially deadly during a power outage, in part because people lack air-conditioning and other ways to stay cool.

• The storms and excessive heat have been fueled by an extreme, prolonged heat dome parked over Texas, where heat indices could once again top 120°F in Texas on Monday, Axios' Andrew Freedman reports.

The big picture: Extreme weather, exacerbated by human-caused climate change, is expected to continue to heavily strain the U.S. power grid in the coming decades.

• The effects of climate-change-fuel weather extremes on the grid may be seen throughout the summer, particularly if the country continues to experience intense heat waves.

Go deeper: Extreme heat affects 45 million people from Southwest to Miss. Valley