Saturday, February 12, 2011

January Alta Snowfall Minimum?

Is there a mid-winter (i.e., January) minimum in snowfall at Alta?  I have heard this bantered about amongst Utah meteorologists since the day I arrived in Utah in 1995.  Let's have a look at the evidence.

According to the Western Region Climate Center, the monthly mean snowfall at Alta is:

Nov: 63.0"
Dec: 81.8"
Jan: 83.9"
Feb: 75.3"
Mar: 80.4"
Apr: 59.6"

Thus, climatologically, January is the snowiest month at Alta, although it is hardly different from December, February, or March.  There is a dip in February, but keep in mind that there are only 28.25 days in February (on average).  If we adjust the February mean for 31 days, as occurs in December, January, and March, the February snowfall normalizes to 82.6", virtually identical to the other months.  

Thus, there is no evidence for a mid-winter snowfall minimum at Alta.  

Whether or not there is a dip in the frequency of major storms (say 10" or more) requires further analysis.  If there is, that would simply mean that there must be an increase in the number of minor storms, or fewer storms of greater intensity, so that the monthly mean remains high.  Perhaps someone can look into this.  

1 comment:

  1. That is interesting. I have been looking at some of the mountain sites too and it is hard to pick out an overall January minimum in either precipitation or snowfall. It sure seems to me that we have had a lot of dry January weather in recent years compared to other winter months. Maybe just a perception, or a temporary trend.