An expected effect of drought has caught parts of the West off guard.

Mini-storms of tumbleweed have invaded the drought-stricken prairie of southern Colorado, blocking rural roads and irrigation canals, and briefly barricading homes and an elementary school.

The invasion of the tumbleweed, an iconic symbol of both the West's rugged terrain and the rugged cowboys who helped settle it, has conjured images of the Dust Bowl of 80 years ago, when severe drought unleashed them onto the landscape.

County governments have spent hundreds of thousands of dollars to get rid of the weeds that have clogged the roads. Counties must also deal with miles of irrigation ditches that are choked by the invasive weed.

Parts of New Mexico, Oklahoma and Texas are also affected.