Fire officials said they expected quick containment of a wind-whipped wildfire ignited by people overnight in tinder-dry brush in a mountain pass near Las Vegas. About 100 county, state and federal firefighters were working to contain flames that spread to as much as 125 acres by dawn. Temperatures had topped 100 degrees in Las Vegas for the past three days, and a pre-dawn shift in winds blew through the area with gusts up to 30 mph. The nearest homes were over a ridge about one mile to the southwest and were not threatened. No injuries have been reported thus far.