Washington, Sep 7 : A storm battered parts of the US state of Arkansas with heavy rain and hail, causing damage to homes and businesses and leaving thousands of residents without power, local media reported. Arkansas Storm Team Chief Meteorologist Carmen Rose said the storm on Wednesday appeared to be a microburst, composed of powerful downbursts from thunderstorms in tightly compacted areas that are usually less than 2.5 miles wide, reports Xinhua news agency. Experts said the high heat and humidity of Arkansas's capital city, Little Rock, had fuelled the storm. As of 9 p.m. on Wednesday night, around 18,000 customers were without power across the state, according to the power outage tracking site PowerOutage.us. Most power outages were in Pulaski County, with 13,062 customers affected, followed by Drew County, with 3,624 outages, according to a report from the NBC-affiliated KARK-TV based in Little Rock. /IANS