Unprecedented October rain rewrites history books

SALT LAKE CITY (ABC4) — We’re reaching the last few days of October. While others are handing out candy, we’ll be handing out an overview of this record-smashing month!

This month we had ludicrous amounts of precipitation across the state and blew records out of the water, largely thanks to remnants from two tropical systems in the Pacific.

Record Precipitation

Generally, Salt Lake City receives an average of 1.32 inches through the month of October, but the first Saturday alone more than doubled the monthly average!

Saturday, October 4^th, dropped an unheard of 2.47 inches of rain, meaning we had over two times more rain in a single day than we had all Summer long! Not only is that 2.47 inches the rainiest October day, but the second rainiest day ever! 

The rainiest day ever recorded in Salt Lake City was 2.64 inches set on May 3^rd of 1901, but there’s a caveat. The 2.47 inches was measured at the NWS station at the International Airport but given that airplanes didn’t yet exist in any form, the 1901 sensor was in downtown instead. That said, this was the most rain our modern-day sensor has ever recorded!

October 4^th brought major flood problems to some areas, especially in Tooele/Rush Valley where they saw a 100-year-flood. The rain totals from Tooele County were out of this world. Two to three inches fell across most of the valley from Stansbury Park to Vernon Hill- Tooele itself measured 2.76 inches.

While Tooele County had the most notable flooding, we still had flooding issues across northern Utah with most places falling in the one-to-two inch range. Many places in the Salt Lake Valley and the northern Wasatch Front saw well over two inches.

Soggy weather returned a few days later, with active skies yet again from the Thursday the 9^th to Saturday the 11^th. This round of moisture came up from southern Utah, bringing record rainfall on Friday the 10^th to the south, including Capitol Reef, Hans Flat, Kodachrome Basin, and Wellington.

We saw the Weather Prediction Center issue a “Moderate” flash flood threat in the southwest for the first time in over three years, and it delivered. At one point there were five simultaneous flood alerts in just Washington County. 

By Saturday, the bulk of the moisture was impacting northern Utah which brought heavy, but not quite record-breaking, rain to the north, although some minor flooding was reported in the Ogden Valley. Nocturnal thunderstorms lit up the night sky on the Wasatch Front Saturday night and dumped buckets of cold rain on Utes fans at the Rice Eccles Stadium.

We only had one day of dry weather before active skies returned on Monday the 13^th and held through that Thursday. On Wednesday the 15^th, there was more flooding in parts of southwest Utah like at Zion.

Meanwhile the north was dealing with hail and rain with snow impacting the Wasatch Back and other mountain valleys. By Thursday morning, Alta (the only resort reporting at the time) had seen eight inches of snow, and the Wasatch Back received about an inch or so for the first flakes of the season.

Within the first two weeks we’d already broken the record October precipitation. Overall, Salt Lake City totaled an outrageous 5.12 inches of rain this month, which obliterates the previous October record of 3.91 inches set in 1981. Out of all 1,800+ months on our record books dating back to the 1800s, this month ranks the 5^th (nearly the 4^th) wettest month of all time!

Keep in mind, October is one of the drier months of the year, which further shows how irregular this month truly was.

Temperature:

The days leading up to our big record-shattering storm on October 4^th were pretty warm, but as the cold front moved in that Saturday morning, we saw temperatures take a plunge into the deep end.

Salt Lake City’s warmest day was Friday October 3^rd with a high of 85 degrees, but within 24 hours temperatures fell by over 30 degrees in the north, falling from the 80s to the 40s in a matter of hours. 

Most valleys were close to freezing overnight lows, we didn’t quite reach it then, but this month did feature our first valley freezes a few weeks later. On the morning of Tuesday, the 21^st most valleys were in the mid 30s, but we squeezed out a few freezing temperatures on the northern end of the Wasatch Front, parts of Utah Valley, and Cache Valley.

It took another week before we experienced widespread freezing temps in valleys. Next Tuesday, the 28^th finally brought the first sub-freezing morning to Salt Lake City and other valleys across the state from Logan to Cedar City (sorry St. George). Overall, Salt Lake City, St. George, and most places in between ended up being approximately a degree above the average high temperature.

What an exciting month it’s been – we needed the rain after a dry Summer, but maybe not so much all at once! We can’t wait to see what November has brewing in the pot!

Stay 4Warned both on-air and online, we are Good4Utah!