At least 136 homes have been destroyed by a wildfire that swept through the mountains around Boulder this week and four people are still unaccounted for, Colorado authorities said Wednesday.

The wind-driven blaze spread quickly in foothills outside Boulder.

A wildfire in the rugged foothills northwest of Boulder forced the evacuation of about 200 homes on Monday.

Cornell University agricultural experts and others worry that the emerald ash borer has the potential to kill ash trees throughout North America.

A mountain bike park in New Mexico offers some new, challenging courses to test the best and most adventurous riders.