Pattern change is arriving now with showers likely today into tonight and Friday with much cooler temperatures across the region. Snowfall is likely in the highest elevations with snow levels dropping down to near 8000 feet by late Friday. Don’t expect much more than a dusting, but it will still be nice to see! It looks like we warm up on Sunday into early next week before another trough affects the area mid to late next week. Details are still hard to come by, but it looks like additional showers and chances for high elevation snow.
Obviously there’s been a lot going on lately on the other side of the country with regard to hurricanes. I was asked on Twitter recently about active Atlantic hurricane seasons and their correlation to Utah snowfall. On it’s face, there’s not much correlation at all. Hurricane season runs from June 1 to November 30 traditionally. So there’s not much overlap with our winter season. However, there are oceanic and atmospheric variables that can affect both, most notably ENSO (El Nino/La Nina). Still, I didn’t think there would be much correlation. I decided to take a very unscientific approach, just compare analogs of active Atlantic hurricane seasons and compare to the subsequent seasons using UDOT’s town of Alta snowfall data that dates back to 1945.
To determine “active” hurricane seasons, I looked at the averages — 10.9 named storms, 5.9 hurricanes, 2.5 major hurricanes each season. To meet the criteria of ‘active’, I pull all years in which they exceeded each of those 3 averages. That left me with 26 hurricane seasons since 1945 that were more active than average on all three metrics. Then I simply checked to see how the subsequent winters fared at Alta.
In the 70+ years of data we have for the Alta-Guard station, the seasonal average snowfall is 497″. In the 26 active hurricane seasons I pulled, the subsequent winters averaged just over 513″ per season. 12 of the seasons were below the 497″ average while 14 were above. I was surprised at how high the average was, but the numbers of above/below was much more of what I expected. It seems that a few very big winters pulled the average up significantly.
So far, 2017 hurricane season is more active than normal. We’ve already at 11 named storms, 6 hurricanes, and 3 major hurricanes. All of which are already above the seasonal averages. We also have more than 2 months of hurricane season left to go.
What can we take from this? The optimists could say that perhaps we are slightly more likely to have an above average year. The realists will say that this means pretty much nothing. I am going to probably side with the latter, but it was fun to just pull some data and have a look.