Lightning in a blizzard

Last night, my family was eating dinner at home during Denver's second blizzard in a week. It's December 28, it's below freezing, heavy snow is falling and the wind is blowing hard. Amy and I both saw a bright flash out the window, and then looked at each other in disbelief. "Was that lightning?" she asked. "It couldn't be, " I said. "It must be some truck's headlights. I've never seen lightning in a snow storm before."

Boom

Did I really just hear thunder? Maybe it was just the wind. But then a few minutes later, we saw another flash. This time, I opened the window a crack and listened carefully. About 5 seconds later, I heard the unmistakable rumble of thunder.