Montana does experience tornadoes, though it is not included in the most active regions known as “Tornado Alley.” These recurring phenomena primarily affect the state’s eastern plains rather than the mountainous regions. While the overall risk is low compared to states like Oklahoma or Kansas, severe weather capable of producing a tornado can occur. Montana’s geography and northern latitude influence the timing and location of these events, making them distinct from those in the central United States.
Montana’s Tornado Activity Level
Montana registers a low incidence of tornadoes compared to the national average, ranking around 31st among U.S. states for frequency. The state records an average of about 10 tornadoes annually, highlighting the infrequency of these events. This low frequency results in a significantly lower overall risk compared to parts of the country where dozens or hundreds of tornadoes touch down each year.
The storms that occur are typically on the weaker end of the Enhanced Fujita (EF) Scale, which rates intensity based on damage. The vast majority of Montana tornadoes are classified as EF0 or EF1, causing minor to moderate damage, such as peeling off roof surfaces or snapping large tree branches. Stronger tornadoes (EF2 or greater) are rare but can cause considerable damage to structures. Historical data confirms that most recorded twisters fall into the weak category, a pattern common to many northern Plains states.
Where and When Tornadoes Strike
Tornado activity is heavily concentrated in the eastern half of the state, particularly across the High Plains region. Counties in the far eastern plains, such as Valley, Fallon, and Fergus, have historically recorded the highest number of tornadoes. This area features the flat, open terrain conducive to the formation and sustainment of rotating columns of air.
The mountainous western regions rarely experience tornadoes because the terrain disrupts the required atmospheric conditions. The few tornadoes recorded in western counties are often weak and short-lived. This distinct pattern means the risk is not uniform, with the sparsely populated eastern plains facing the highest probability of an event.
Tornado season typically runs from late spring through mid-summer, with peak activity occurring during June and July. This timing is later than the peak season in the southern Great Plains due to Montana’s northern latitude, which delays the arrival of warmer temperatures. Most tornadoes form and touch down during the late afternoon and early evening hours, often peaking around 5:00 PM local time.
Staying Safe During Severe Weather
Preparation for severe weather involves having multiple methods for receiving official alerts from the National Weather Service (NWS). Residents should utilize a NOAA weather radio, local television/radio broadcasts, or mobile phone apps to monitor for Tornado Watches and Warnings. A Tornado Watch means conditions are favorable for development, while a Tornado Warning means a tornado has been sighted or indicated by radar, requiring immediate action.
When a warning is issued, seek shelter in the lowest level of a sturdy building, ideally a basement or a safe room. If a basement is unavailable, move to a small interior room, like a closet or bathroom, on the ground floor, keeping walls between you and the outside. Stay away from windows and protect your head and neck with your arms or a sturdy object.
If caught outdoors or in a vehicle, attempting to out-drive a tornado is not advised, and overpasses do not offer protection. The safest course of action is to abandon the vehicle and find the nearest low-lying area, such as a ditch or ravine. Lie flat in the ditch while covering your head. Mobile homes are not safe during a tornado, and occupants must move to a more substantial shelter when severe weather threatens.