Only one thing could eclipse the news that 2017 was Austin’s hottest year since the National Weather Service began keeping records in the 1890s: Hurricane Harvey.
According to weather service data, 2017’s average temperature was 72.1 degrees, only a tenth of a degree higher than the previous hottest year ever, 2011 — a record-setting year when Austin was in the throes of a historic drought, and the city weathered an unprecedented 90 days of 100-degree heat.
The data show, however, that had it not been for Hurricane Harvey, 2017 could have been a lot hotter.
Before Harvey, the year was already likely to be remembered most for Austin’s warmest winter, which included four freak tornadoes in February. As much as Austin’s 42 days of triple-digit temperatures last summer were seared into our memories, no one was likely going to forget the sight of the rare double snowfall in December.
Austin’s year in weird weather began with an unusually warm, soggy January that produced 4.13 inches of rain — nearly 2 inches more than normal — and posted a historically high average temperature of 56.7 degrees, which was 5.2 degrees above normal.
The early bloom of wildflowers the following month should have been the tip-off that Austin would conclude its warmest winter ever with its warmest February ever. The average temperature for the month was 64.5 degrees, about 3 degrees more than the next-warmest February, which was back in 1999.
But the same winter that delivered the first 90-degree day of 2017 on Feb. 23 — about two months earlier than normal — also produced four nighttime twisters on Feb. 19 and 20. Two tornadoes ravaged southeastern Williamson County, one twister touched down in Hays County near San Marcos and Kyle, and another struck near Niederwald and Mustang Ridge in Travis County.
“We’ve just really had no winter,” Troy Kimmel, a University of Texas meteorologist and instructor told the American-Statesman’s Marty Toohey in March. “We saw winter on the calendar, but we didn’t see it in real life.”
The above-normal warmth continued for another month, as Austin saw its warmest March ever. The average temperature of 68.6 degrees broke a 110-year record.
The weirdness persisted in April, when a series of stalled thunderstorms on April 11 flooded communities from Killeen to San Marcos, but largely shunned Austin. The city’s lackluster rain totals in April became an early indicator for the dry seasons to come. The month, which normally sees 2.09 inches at the Camp Mabry weather station, produced only 1.22 inches there.
May, historically Austin’s wettest month, delivered only 2.86 inches of rain, well short of the 4.44 inches it normally produces. June clouds did drop about 3 inches of rain, but the total was still more than an inch less than normal. July was even worse for rainfall: A month that typically sees 1.88 inches recorded less than a quarter-inch.
Then came Harvey.
The zombie tropical cyclone had broken up near Mexico’s Yucatan Peninsula only to be reborn stronger, fueled by abnormally warm water in the Gulf of Mexico. The storm smashed into Texas twice, and it fueled storms that dumped as much as 29 inches of rain east of Smithville and caused the Colorado River to top its banks in Bastrop and Fayette counties. The Colorado flooded La Grange when the river crested at 54 feet, its highest level in 104 years.
As Harvey thrashed the Texas coast over four days, from Aug. 25 to 28, Camp Mabry received nearly 8 inches of rain while about 10 inches fell at Austin-Bergstrom International Airport.
Harvey’s damaging winds and heavy rains also briefly shut down Austin’s summer swelter. Once the hurricane arrived in Texas, temperatures in Austin on Aug. 26 reached only 76 degrees, the lowest that temperatures have ever peaked on that date.
By month’s end, 10.44 inches of rain had fallen in Austin, and August’s average temperature was 85.3 degrees, about half a degree cooler than normal.
Austin spent much of September drying out from Harvey, and temperatures largely hewed close to normal ranges. The average temperature was 79.9 degrees, just 0.1 degree cooler than normal. But the 2.03 inches of rainfall came in nearly an inch less than normal for that month.
La Niña, the seasonal cooling of the waters in the eastern Pacific Ocean that can drive weather patterns in Texas, began to take hold in October. In Central Texas, La Niña events can translate into milder, drier weather, depending on the time of year. For Austin, that meant seeing “wet” months like October only produce 1.76 inches of rain when it typically delivers 3.88 inches; or seeing November eke out 0.12 inch of rain when it normally gets almost 3 inches.
But December’s rainfall helped make up for the lack of moisture in the fall. Not only did the month see 4.31 inches of rain — nearly 80 percent more than normal — but Austin witnessed what some might consider a holiday miracle: snow on the nights of Dec. 7 and 31.
Drought and lake levels
The dry fall and winter in 2017 meant that Central Texas and the rest of the state is seeing more widespread drought conditions. According to data from the U.S. Drought Monitor, a consortium of academic and federal government researchers, Texas is starting 2018 with about two-thirds of the state abnormally dry or facing moderate to severe drought. That proportion was only 18.5 percent at this time in 2017.
Despite having some typically wet months prove drier than normal last year, the water supplies in the Highland Lakes appear to be holding up for now. Going into 2018, the water elevation at Lake Travis as of Thursday was about 669 feet above mean sea level — slightly above the historical January average, but still a decline of about 14 feet from the same time in 2017. Lake Travis — an aquatic playground for Central Texas as well as a critical water source — was 82 percent full, data from the Lower Colorado River Authority show.