As 2015 nears its conclusion, it may finish with the fewest tornado fatalities in the United States on record.
There have been only 10 tornado-related fatalities in the U.S. so far this year, significantly lower than the 20-year annual average of 80 tornado fatalities.
According to Mike Smith, vice president of AccuWeather Enterprise Solutions, one of the primary factors that contributed to such a low number was the location of where tornadoes touched down in 2015.
While some twisters did threaten cities and towns with high populations, a majority of tornadoes struck the Plains, where there are large open fields and widely separated towns.
It is in these open, unpopulated areas where some of the strongest tornadoes of the year occurred, posing significantly less danger than if they tracked near a high population center.
"The storm track was farther west out toward the Rockies this year, with tornadoes threatening the open country," AccuWeather Severe Weather Expert Henry Margusity said. "This shift is part of the El Niño pattern, which strengthened the Pacific jet stream."
El Nño is defined by warmer-than-normal waters in the equatorial Pacific Ocean, and it affects weather patterns around the world.
The jet stream is a zone of strong winds in the upper levels of the atmosphere. The Pacific jet stream extends from the Pacific Ocean rather than the polar region, so it can help to stir moisture into the U.S.
Another factor that has helped to reduce the number of tornado-related fatalities is the advanced warning systems that are in place. This includes tornado watches and warnings that alert the public of potentially dangerous storms and tornadoes.
People can even get severe weather alerts from smart phones or smartwatches.
Smith added that without these types of warning systems, more people would be killed by tornadoes every year.
In addition to 2015 having a significantly lower fatality rate with tornadoes, the overall number of tornadoes was below normal.
As of Dec. 16, there have been 1,177 reported tornadoes, which is below the annual average of 1,355, according to NOAA.
The slow start to the spring severe weather season is one of the main reasons why 2015 has been a year with fewer-than-normal tornado reports.
Typically, there are several severe weather outbreaks that spawn tornadoes during January, February and March, but this year there were very few outbreaks during these months.
"Cold, dry air blanketed much of the country through March, suppressing the threat for tornadoes," Margusity said.
The severe weather season ramped up during May and June, with several significant tornado outbreaks, as warm and moist air returned.
According to AccuWeather Senior Meteorologist Alex Sosnowski, severe weather could be a threat in the central U.S. during Christmas week. The storms may be capable of producing tornadoes.