A satellite photo from the National Weather Service. They believe the blue images to be clouds of monarch butterflies.

Last week the U.S. National Weather Service posted satellite photos to their Facebook page of large clouds over the St. Louis area, which they identified as monarch butterflies.

“High differential reflectivity values as well as low correlation coefficient values indicate these are most likely biological targets,” they wrote about the clouds. “High differential reflectivity indicates these are oblate targets, and low correlation coefficient means the targets are changing shape. We think these targets are Monarch butterflies. A Monarch in flight would look oblate to the radar, and flapping wings would account for the changing shape! NWS St. Louis wishes good luck and a safe journey to these amazing little creatures on their long journey south!”

April Fools Day is about six months from now, so this apparently is no joke.

In fact, media outlets (click here or image below for video) have reported that the clouds were over 250 miles wide, and that they spread into Illinois and other parts of Missouri:

This is at least the second time this summer that clouds of insects were large enough to be spotted by satellites, as earlier this year billions of mayflies were spotted over the Mississippi River.