Posted: Apr 30, 2013 10:50 PM by STORMTracker Weather Team
Tornadoes aren't very common in the Treasure State, but some areas have what it takes for twisters to develop.
Supercell storms, which produce tornadoes, require an abundance of low level moisture and wind shear.
This is mostly found in the Central Plains and Midwest in an area known as Tornado Alley.
Since Montana is so far north, moisture from the Gulf of Mexico is hard to come by.
Most of the state's moisture comes from the Pacific Ocean and is typically brought in by upper level winds.
However, once in a while, a pattern will develop that allows low level moisture to flow north into eastern Montana.
It's this same area which also sees favorable wind shear, or a turning of winds with height.
Since 1950, Valley County tops the list for most tornadoes in Montana with 38.
Fergus County comes in second with 27.
Western Montana isn't immune from twisters, but the Rocky Mountains block low level moisture from reaching that side of the Divide.