AUSTIN (KXAN) — Central Texas has seen a busy severe weather season so far this year. Six tornadoes touched down in the 15-county KXAN viewing area on March 21, including an EF-2 that injured 16 people in Round Rock.

Another tornado was confirmed near Florence on April 13. It produced EF-1 damage in Williamson County, before strengthening to an EF-3 in neighboring Bell County.

From 1950 to 2021, the region has averaged 5.7 tornadoes per year, according to data from the National Oceanic and Atmospheric Administration (NOAA).

The NOAA data shows 423 tornadoes were reported in the KXAN viewing area between Jan. 1, 1950 and Dec. 31, 2021. NOAA splits tornadoes into multiple “segments.” If a tornado crosses a county or state line, it begins a new segment. Therefore, long-track tornadoes that are on the ground for an extended period of time may technically be counted more than once, if it crosses into a new county.

The most tornadoes reported in a single year was 20 in 2015, including the largest outbreak in Central Texas history. A total of 17 tornadoes touched down in the area over Memorial Day weekend, the strongest being an EF-2 twister in Milam County.

Zero tornadoes were reported in seven years since 1950, the most recent being 2013.

Statewide, tornadoes are most common during the spring severe weather season, particularly in May. In the KXAN viewing area, the stats reflect the same: May has seen the most tornadoes since 1950, 129 in total. That breaks down to an average of 1.8 tornadoes every May.

Six tornadoes were confirmed in the region in March 2022, well ahead of the March average of 0.5 tornadoes.

From 1950 to 2021, the most tornadoes locally were reported in Travis County: 68 in total. Williamson County is right behind, with 67. Bastrop County is third, with 33 tornadoes.

Llano County has seen the fewest: just 11 in the 72-year timespan.

The National Weather Service uses the Enhanced Fujita Scale to determine how strong tornadoes are. The NWS does this by looking at damage caused and estimating the wind speeds the tornado likely produced. In Feb. 2007, the NWS revised the original Fujita Scale “to reflect better examinations of tornado damage surveys so as to align wind speeds more closely with associated storm damage.”

The majority of tornadoes in the KXAN viewing area are weak, according to the Enhanced Fujita Scale. Of the 423 tornadoes reported between 1950 and 2021, 73% were rated either F-0/EF-0 or F-1/EF-1.

Violent tornadoes — those rated F-4/EF-4 and F-5/EF-5 — are much rarer. Only three such tornadoes were reported during the same time period, accounting for 0.7% of all tornadoes. The most famous example is the 1997 F5 tornado that hit Jarrell, causing 27 deaths, 12 injuries and $40 million in property damage.

Of the six tornadoes confirmed so far in 2022, three have been rated as EF-2, and three have been rated EF-1. The map below shows the strongest tornadoes reported in each county. The 1997 F-5 Jarrell tornado occurred in Williamson County. Mason and Travis counties are the only other counties to experience at least an F-4/EF-4 tornado.

Llano County, meanwhile, has never had a tornado stronger than an F-1/EF-1.

The March 21 outbreak that produced six tornadoes locally ties for eighth for most tornadoes reported in a single calendar day.

Eleven tornadoes have been reported on a single day three separate times: Sept. 20, 1967, Aug. 10, 1980 and, most recently, Nov. 15, 2001.

KXAN has also analyzed tornado data on a statewide level. Click here to check out our interactive maps and charts.