Excessive heat poses dangers

Chattanoogans and residents of the surrounding area are accustomed to dealing with the high heat and humidity of a typical summer. It is far more difficult for residents of the nation's more temperate areas to cope with occasional periods of extremely high temperatures and humidity. Millions of Americans who live in an area stretching from the Oklahoma through the Ohio Valley to the East Coast will have to learn to adapt quickly.

A huge mass of extremely hot air and excessive moisture -- called a "heat dome" by meteorologists -- has baked parts of the nation's midsection for days. It's now on the move, sliding to the north and to the east. It will bring record-breaking temperatures and humidity to areas more accustomed to warm rather than hot weather. More than 25 states likely will be placed under heat advisories or excessive heat warnings before the weekend ends.