States with a low annual rainfall and high summer temperatures are more prone to wildfires. Roads may be closed during large fires to reduce the risk of collisions in areas affected by the smoke. In June 2011, The New Mexican reported a fire in the Carson National Forest that resulted in the closure of U.S. Highway 518. Also in June 2011, the Arizona Central website reported that wildfires across the state forced the closure of approximately 150 miles of highway. Weather forecasters can use wind direction to predict which way the fires will spread, and will issue warnings for areas likely to be affected.
During the winter, storms can generate snow and ice, which may lead to roads being closed. Snowdrifts may completely block passage, while blizzards and ice can make driving dangerous. Check the local weather during the winter for any storm warnings. Some states close certain roads as a matter of course during the winter. Examples include the Mount Evans Byway and the Pikes Peak Toll Road in Colorado, the The Beartooth Highway in Montana and the North Cascades Highway in Washington state.
Flooding after heavy rainfall causes thousands of road closures every year. Meteorologists issue storm warnings to areas likely to be hit by flooding. Flooding can make roads impassable and cause severe damage to the road surface. In April 2011, Yahoo! News reported that larges portions of Illinois Route 3 were closed after heavy rainfall caused the Mississippi River to overflow its banks. One month later, the Internashonal reported that an overflowing Mississippi caused a portion of U.S. Highway 61 to close.
Forecasts of gales or even hurricanes inevitably lead to road closures. Trees are uprooted or lose their branches, some of which may end up blocking roads. Debris blown from other vehicles and surrounding building may also block roads. In May 2011, the Record Herald reported that part of Interstate Highway 81 in Franklin County, Pennsylvania, was closed after a tractor-trailer was blown over by strong winds. The following month, Newsnet5 reported that Ohio Route 84 in Cleveland was closed after severe winds caused a tree to fall on to the road, bringing surrounding power lines down with it.
