Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of Wolverine World Wide (NYSE: WWW) have gotten crushed today, down by as much as 10%, after the company warned about weakness in European markets.

So what: Roughly a quarter of last year's sales were generated in Europe, so weakness there could certainly hurt the footwear and apparel maker's results. At a retail conference, Wolverine World Wide disclosed that it will "fall modestly below" its prior guidance primarily due to continued challenges it faces in Europe.

Now what: Europe, Middle East, and Africa sales so far this quarter have fallen by double digits relative to a year ago. The company cited a combination of weather and economic conditions as contributing factors. Previous guidance called for low-to-mid-single-digit revenue growth and roughly flat earnings, but Wolverine now concedes it can't hit that target. On the bright side, the U.S. wholesale business "remains solid," but that's little consolation to shareholders today.

Interested in more info on Wolverine World Wide? Add it to your watchlist by clicking here.

Fool contributor Evan Niu holds no position in any company mentioned. Click here to see his holdings and a short bio. The Motley Fool has a disclosure policy. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. Try any of our Foolish newsletter services free for 30 days.