Was driving home, heading south on Commercial Avenue, on the south side of San Antonio. We noticed a large flash of light in the south eastern part of the sky. Each flash was blue in color. Flashes lasted only a few seconds, but continued for several minutes around the San Antonio River and Loop 410 area. There was no accompanying sound, smoke or any reports of electrical power being lost. The flashes light up the entire portion of the sky. There was a gas main that caught fire, but it was reported at 0100 hrs a full 5 hours after these flashes were observed.