David Zalubowski, AP
A painted lady butterfly flies near daisies in a garden in downtown Denver Wednesday, Oct. 4, 2017.

SALT LAKE CITY — California received an unexpected surprise this week — a giant butterfly migration.

CNN reports that California deserts are experiencing swarms of painted lady butterflies arriving from Mexico this week.

"This is the biggest outbreak since 2005," said Art Shapiro, a professor at the University of California, Davis.

See videos and photos of the butterflies below.

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  • Shapiro said the painted ladies “tend to thrive when there's a super bloom … because there are so many plants for the butterflies to lay their eggs on and for caterpillars to eat,” according to CNN.
  • These butterflies tend to hang around the U.S.-Mexico border until they fly north for the spring season. They travel back south for the fall, according to CNN.

So why so many butterflies? Well, California is actually experiencing one of its wettest winter seasons on record in recent memory. I wrote about how the state is no longer experiencing a drought, ending a 376-week span dating back to Dec. 20, 2011.

  • And, according to the Los Angeles Times, the increased rain has led to a super bloom in flowers across California, which has led to the painted ladies migrating back into the state earlier than in previous years.