Trish Tracy of the Tucson fire department told KNXV-TV the playhouse was blown across three lanes of traffic and landed on a median Saturday. Tracy says the children suffered serious but nonlife threatening injuries. The National Weather Service says the incident was caused by a weather phenomenon known as a dust devil, in which a column of air can rotate up to 60 mph. It was the second such incident this year in the area. Officials in Marana, Arizona, say a 10-year-old girl hurt her head in February when she fell out of a bounce house lifted by wind.