SPOKANE, Wash.—About a dozen deaths in Washington and Oregon may be tied to an intense heat wave that brought scorching temperatures to the Northwest and caused one power utility to impose rolling blackouts amid heavy demand. The dangerous weather that gave Seattle and Portland consecutive days of record high temperatures exceeding 100 degrees Fahrenheit (37.7 degrees Celsius) eased in those cities on Tuesday. But inland Spokane, towns in eastern Oregon and cities in Idaho saw temperatures spike. The National Weather Service said the mercury reached 109 F (42.2 C) in Tuesday in Spokane—the highest temperature ever recorded there. About 9,300 Avista Utilities customers in Spokane lost power on Monday and the company said more planned blackouts began on Tuesday afternoon in the city of about 220,000 people. “We try to limit outages to one hour per customer,” said Heather Rosentrater, an Avista vice president for energy delivery. She said about …