You’ve got to be kidding me!
I looked out the window of my Omaha home on the morning of October 10, 2009, and saw a few inches of fresh snow covering the ground. Sure, we had been talking up the chance for a little snow to mix in overnight in the weather office. And being the eager weather weenie, I had even gotten up with my husband in the middle of the night to watch the first flakes flying. But 5 inches? In early October? I was not ready for this!
As the climate person in our weather office, I started receiving questions almost immediately: Does a snow in October predict a hard winter? What has happened in other years when it snowed in October?
Well, I knew about one October snow in the past: October 1880, the ominous foreshadowing of the fierce Hard Winter.
I had just started to tinker with studying The Long Winter in 2009, but I had not yet grabbed the data to put dates to the big events. I started that work just two weeks later, according to my email files, spurred into deeper research by the hard winter unfolding around me.
We don’t have weather observations in DeSmet for the winter of 1880-1881, at least not documented ones. We don’t even have them for Huron. We do have several sites around the region, surrounding DeSmet in just about all directions. (See the map below for a reminder of where the data sites are located.) Those sites all have daily records for the Hard Winter, at least as much as observations were taken in those years. Observers did not measure snow in the early 1880s, but with measurements of both temperatures and precipitation, we can make a pretty educated guess about whether the precipitation fell as rain, snow, or both. Occasionally, observers were even helpful enough to put in their notes that snow had fallen.
Map of sites with weather observations in 1880-1881 surrounding DeSmet.
For many of the sites, here is the weather that was observed around mid-October:
Let’s look at these closely. On the 13th and 14th, the high temperature was quite warm around the area, ranging from the upper 50s to the north (Fort Sisseton) to the lower 70s southward (Omaha and Ft. Randall). Even the low temperatures were above freezing everywhere except in Fort Sisseton. These are not our blizzard days!
On the 15th, cooler air is clearly working its way into South Dakota. Both Fort Randall and Fort Sisseton only reached the lower 30s for highs, and Fort Randall even reported snow, though it was dry in Fort Sisseton. Even though they are pretty close to each other, Yankton was quite a bit warmer on the 15th, reaching 54 degrees, and Omaha and Minneapolis/St. Paul both stayed warm. This says to me, with a “weather eye” on the observations, that there was a strong cold front moving in from the west/northwest, while rain was spreading up from the south and changing to snow as it encountered the colder air.
The snow really got going in the area overnight on the 15th and into the 16th. Cold air reached all of the sites except for Fort Bennett, which seems to have been just far enough out of position to miss the core of the storm. The precipitation in Omaha probably was a very cold rain or a rain/snow mix on the 15th, while Fort Sisseton was reporting snow and even Minneapolis/St. Paul probably saw rain changing to snow during the day. Snow continued into the 17th at both Fort Sisseton and Minneapolis/St. Paul, with temperatures near or below freezing at all sites. Snow even continued into the 18th at Minneapolis/St. Paul, with some light snow appearing likely at Yankton and Fort Randall.
Once the storm departed the area, temperatures bounced back rather quickly, with highs in the 40s to 50s across the area by the 19th.
So, that covers the snow. Now, let’s talk about the wind.
We have all kinds of gadgets to measure wind these days, but back in the early 1880s, it was largely estimated based on technology like wind socks and the Beaufort scale. I have these records, too, but I won’t scare you by posting them here. They’re not pretty. Let’s just say this: It was windy during the October snow. Winds were strongest on the 15th and 16th, though Fort Sisseton got into some wind even on the 14th. More importantly, I can see that the wind direction shifted from southwesterly ( a warmer wind) to northwesterly (a cold wind) on the 15th.
Now, it’s time to put together the whole story, from the weather perspective!
A storm system moved up from southwest Colorado toward eastern Nebraska, while cold air was dipping out of Canada due to a weaker storm system moving through North Dakota into Minnesota. The initial shot of cold air brought near-freezing temperatures and a little bit of precipitation up north on the 14th. The low pressure system deepened on the 15th as it got spinning in eastern Nebraska, pulling cold air around behind it while it brought moisture up from the south. Then, the low pressure just sat there for a while and deepened. As it got deeper, the winds behind it – in eastern South Dakota – got stronger. The storm stayed in the area of northwest Iowa to southern Minnesota through the 16th, then pulled away into northern Michigan on the 17th, leaving cold air and breezy conditions behind it.
Snow in October is always kind of stunning. It shocks us into the reality that winter is approaching quickly, and that we’d better hurry our preparations before we really get caught. In Laura’s case, the October blizzard indeed was the first strike of many during an exceptionally cold and snowy winter. In my case, the October snow also was the first strike of many during a winter that started among the coldest and snowiest. Luckily, for me, the winter ended a little more “normally” once we got past mid-January, which I can probably at least partially credit to climate change causing warming temperature trends. I can’t imagine what it was like to endure another three months.
Oh, and if you were wondering: No, a snow in October does not necessarily predict a hard winter. Snow has been measured in October in Huron 43 of its 120 years with snow records. The winters following those snows had no tendencies – they were pretty evenly split between warm winters and cold ones, snowy winters and not snowy ones.
*Thank you to the person who corrected my math in the comments :). Indeed, 2012 is 132 years after 1880, not 131!