Nearly 100 million Americans face extreme heat

Extreme heat is sweeping across the United States. Nearly 100 million Americans are under heat-related warnings and advisories — and the National Weather Service says it may be weeks before things cool down.

Many parts of the South and Midwest are seeing temperatures above 100 degrees Fahrenheit and a vast swath of the Southwest is scorching.

The heat isn't just unpleasant or inconvenient: For vulnerable populations, it's downright dangerous.

Here & Now's Robin Young speaks with Matthew Cappucci, a meteorologist for the Washington Post's Capital Weather Gang.