Most people who live in cold regions have seen signs that say "bridge freezes before road," but do you know why bridges freeze first?
There are actually several reasons why bridges freeze before roads. The first is that a bridge is exposed from below and above, unlike a roadway. Roads don't freeze over as quickly because they can take advantage of insulation and warmth from the soil below. Bridges, on the other hand, are beset with cold temperatures from all sides, which can cause them to ice over quickly. Bridges also freeze rapidly because many of them are located over cold spots, like frozen rivers or deep ravines.
The third reason that bridges freeze before roads is their construction. The materials used in the core of a bridge are excellent heat conductors. As a result, they draw heat out from the inside of the bridge, transferring it to the surface where it is quickly lost when ambient temperatures are very cold. Bridges often quickly reach the general air temperature, so when the thermometer reads 32 degrees Fahrenheit, the bridge will freeze.
Why can different types of precipitation be seen on Earth while temperatures remain constant?
Dangerous flash flooding is captured as an arroyo becomes filled with water in Carson Valley, Nevada.
The RealFeel Temperature uses an equation to determine how it actually feels outside.
Knowing what the different advisories, watches, and warnings mean will lead to more informed decision making when a winter storm threatens a particular area.
How can you determine if and when the ice is thick enough for safely going out on?
Seeking shelter in the event of a tornado could save your life, but is there really any safe place to hide?
Driving on a 90-degree angle away from the tornado is a good strategy to follow in order to distance yourself from the tornado.
Supercell thunderstorms have been responsible for major tornadoes that have demolished parts of the U.S.
After a cold, clear winter night without much wind, the ground and nearby tree branches may be covered by tiny, white ice crystals.
A major cause of post-snow flooding are ice jams in waterways.
Door County, WI (1985)
Up to 30 in. of snow over the past 2 days in parts of Door County, WI (NW of Green Bay). Lake squalls.
Johnstown, PA (1986)
Lightning during a snowstorm set fire to a church and caused damage.
Boston, MA (1861)
46 degrees on this date, -14 degrees on the 8th, and 60 degrees on the 11th.