As many as six tornadoes may have touched down Thursday afternoon in the D.C. region. Two of them have been confirmed by the National Weather Service — one in the District itself — and surveys are ongoing in other damaged areas.

Surprisingly, tornadoes aren’t all that uncommon in the D.C. region, but we rarely see very strong or long-lived ones, and tornadoes in the District are extremely uncommon.

Our typical tornado season runs from about April to September and peaks at the same time thunderstorms do in the middle of summer. The region has seen tornadoes in winter, too, although December has the least. April brings some of the most significant tornadoes in the region, like the F4 that struck La Plata on April 28, 2002.

Most years have at least a few days with a notable tornado threat, but many of those days end up tornado-free. On average, storms in our region generate a handful of tornadoes each year. Of course, it’s possible some small and weak tornadoes — like Thursday’s — go uncounted in our more sparsely populated areas. And sometimes it’s difficult to differentiate brief, weak tornado damage from a straight-line wind gust.

There have only been two days with tornadoes in the city in modern records since 1950. One was very brief in 1995, knocking down a few trees near the Potomac. In 2001, in the same storm that dropped the F3 tornado on College Park, two separate tornadoes may have affected the city. A weak tornado crossed from near the Pentagon into western parts of the District. The second touched down near the D.C. line before moving into College Park, Md., where two people were killed. That fact is difficult to track down — the NWS database shows it touching down in D.C., but many records do not count it as a D.C. tornado.

The last time a tornado touched down inside the Beltway was Oct. 15, 2014, in Alexandria. It was weak with minimal damage. Before that, on June 1, 2012, multiple tornadoes affected the area. We had a moderate risk that day from the Storm Prediction Center. There were eight tornadoes in the CWG region, all north of the city and all weak. It was the second-highest number of tornadoes Maryland has seen in a single day.

In a two-county radius, the last significant April tornado event in the greater D.C. metro area occurred in 2011. On April 27, a “super outbreak” was happening in the South — EF-4s and EF-5s rolled through Alabama and killed more than 350 people. All of the tornadoes that occurred in the D.C. area that day were rated EF-0, the weakest on the scale.

The most damaging tornado in the District occurred on Nov. 17, 1927. The strong twister formed in Alexandria before tracking into the capital where it carved a path through Southeast. It was on the ground for 17 miles and tore through Navy Yard and its surroundings. More than 400 buildings were damaged and 50 people were injured.

Arguably, the city’s most famous tornado was in 1814. This was the day British troops torched the White House. The storm is said to have extinguished the flames and many were reported killed or injured. It’s unknown whether it was truly a tornado, but historical descriptions match (and it makes for a good tale).