A heat wave is threatening to melt plans for America's 250th birthday, making parades and parties uncomfortable at best and downright dangerous at worst. At least 11 states are expecting temperatures above 100 degrees over the holiday weekend. Kris Van Cleave reports and Rob Marciano has the forecast.

A heat wave is threatening to melt plans for America's 250th birthday, making parades and parties uncomfortable at best and downright dangerous at worst. At least 11 states are expecting temperatures above 100 degrees over the holiday weekend. Kris Van Cleave reports and Rob Marciano has the forecast.