(Tropical Storm Bill) that had a similar impact on Houston, causing several highways to be closed due to the bayou overflowing; this event followed flooding from May 24–26. Another similar storm in April 2016 resulted in widespread, severe flooding across Houston and surrounding suburbs in an event later known as the "Tax Day Floods". In late August 2017, Hurricane Harvey flooded Houston, causing severe widespread damage and at least 14 deaths. On the night of May 18, 2021, a large and intense severe storm impacted Houston. It caused up to 4 inches of rain per hour in some areas. The storm could've done more because was moving faster than they thought. Tornadoes Unlike Dallas, Houston is not in Tornado Alley; however, smaller tornadoes can occur during severe weather. They are most likely to be found along frontal boundaries of an air mass during the spring months. Tornadoes in Houston usually measure a weak EF1 on the Enhanced Fujita scale and cause light to moderate damage to well-constructed buildings. The strongest recorded tornado in Houston history was an F4 on November 21, 1992, part of a large outbreak of tornadoes in Harris County. Winter storms There are usually a few days of freezing (≤) temperatures each year, though the average low in January, the coldest month, is still only or . Snow falls infrequently in the Magnolia City. When it does occur, it usually melts immediately on the ground with light accumulation on roofs and raised surfaces. Only very uncommonly does it accumulate on the ground. Since 1895, it has snowed 39 times in Houston at an average of about once every 3 years, though some decades have several instances of recorded snowfall while others have only one each (e.g., the 1930s and 1950s) and one decade where there wasn't any snowfall (1990s). The last recorded snowfall in Houston was on February 15, 2021. There were more incidences of snow in the 1980s on average than any other decade recorded, but the 2000s also witnessed more frequent and record-breaking snows. February 14–February 15, 1895: of snow, its largest snowfall from one storm on record. February 12, 1960: of snow. January 11, 1973: of snow. December 22, 1989: of snow with a record low of on December 23. December 10, 2008: Tied the earliest accumulating snowfall record. December 4, 2009: Broke the earliest accumulating snowfall record. December 7, 2017: 0.7 inches (2