Heavy rain and lightning cause power outages and a Flash Flood Warning overnight. The rain continued into the morning. National Weather Service Doppler radar estimates show a band of heavy rain that fell early this morning from just southwest of Huron to near Wessington Springs. A pocket of six inch rainfall is indicated in the Alpena area. Lightning may have cause an transformer explosion at the substation behind the Karl’s store at 21st Street. Northwestern Energy crews fought the heavy rain and vivid constant lightning to get power back on around four this morning, after a roughly two hour outage for residents south of 21st Street. The traffic signal at 21st and Dakota Avenue lost power, forcing authorities to place stop signs at the intersection to prevent accidents. Power went out this morning in the area of 4th and Idaho Southeast. Rainwater also caused ponding on US. Highway 14.