Authorities: Destructive grass fire in Oregon was arson

PORTLAND, Ore. — A wind-driven grass fire that roared to life during rush hour in a residential neighborhood of Portland, Oregon, and prompted evacuations was intentionally set, fire authorities said Tuesday.

The Monday blaze damaged five buildings, destroyed 50 cars in a parking lot and sent people running from their homes as residents across the city gawked at the huge plume of black smoke.

Investigators want to speak to anyone who may have seen how the fire started in an abandoned driving range, Portland Fire and Rescue Lt. Jason Anderson said at a news conference.

Officials declined to say what led them to believe the fire was arson.

No one was hurt and firefighters were able to contain the flames to an area about the size of 2 ½ city blocks.

A grass fire in a densely populated area of a big city is unusual and comes as a late-summer heat wave in the region pushed temperatures to 96 degrees (35.5 Celsius) by Tuesday afternoon.

Fire authorities issued a burn ban effective immediately in the metropolitan area because of high temperatures, low rainfall and dry conditions.

The Lumberyard, an indoor BMX bike park and camp, was damaged in the blaze and its owners said Tuesday there was still no power.

"We have immense gratitude for Portland's fire, police, and emergency services; without their skill and courage, the toll would certainly have been worse," they posted on Facebook.