I was with some friends last night in Rochester, MN when some of them showed up and said 'Did you see all of the lightning?' We looked to the north and sure enough, there was just non-stop lightning going on! But there was no rain or thunder, just constant flashes of lightning. So what the heck was going on?

It was going on for a few hours at least. I was able to catch an ok video of it while on the way home.

We all kept expecting it to start downpouring on us but the radar showed no chance for rain all night. It was so strange! I did, however, notice a huge storm that was going through the northern part of the Twin Cities. But I thought, 'there's no way that's what we're seeing'. Here's a screenshot from Weather.us from about 8 PM yesterday (Tuesday, Sept. 20th).

Weather.us
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I looked it up when we got home and it turns out, lightning that's totally silent with no thunder or rain is actually called heat lightning. According to NOAA, it's "lightning from a distant thunderstorm just too far away to see the actual cloud-to-ground flash or to hear the accompanying thunder."

NOAA goes on to say that "mountains, hills, trees or just the curvature of the earth prevent the observer from seeing the actual lightning flash." What we're seeing with heat lightning is the "light being reflected off higher-level clouds."

So the lightning we were seeing was actually from the storm north of the cities! That's wild! I heard from a friend who lives up there that the storms were pretty nasty too so it makes sense that we'd see lightning from a crazy storm like that.

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