The warm winter cut into Avista Corp.’s first quarter earnings through lower sales of electricity and natural gas, company officials said this morning. The Spokane-based utility reported first quarter income of $46.4 million, or 74 cents per share, compared to first quarter income of $48.5 million, or 81 cents per share, during the first quarter of 2014. Avista reported operating revenues of $446 million during the quarter. A Washington rate increase that took effect Jan. 1 helped offset reduced power sales, company officials said. The above-normal temperatures and rainfall during the first quarter also resulted in strong hydropower generation, which benefited Avista’s bottom line. In addition, the cost of electricity and natural gas purchased by the utility was below expectations. “Excluding the impacts of weather, we had a solid first quarter,” Avista Chairman and CEO Scott Morris said in a prepared statement. The company is expecting 2015 earnings in the range of $1.86 to $2.06 per share.