La Nina?

Traveling around town, campus and even my house it is becoming apparent, the typical Northwest powder producer La Nina is losing its magical power in the eyes of the masses.  Where is it? Why can I count the number of powder days I've had this year on one hand?  The idea of a weak winter has driven me to do some research in order to find out what is going on and just how bad we really have it.

Bridger Snow Report for 2/1/2012. (Credit: BridgerBowl.com

Weather is sporadic and can be an extremely difficult thing to keep tabs on.  With a limited data set to work with there is great uncertainty.  Usable weather data is limited to about a 100 year history in the the US.  With detailed measurements such as snow pack depths, river discharges and other fine tuned observations, this data has been around for even shorter. To add to the mystery of weather, the measurement devices and techniques used in the past compared to today have changed so dramatically its sometimes hard to imaging what sources of error could have been changing data back then.

Old Way
(Credit: Cliff Mass Weather Blog)

New Way
(Credit: University of Tennessee)

So when we have a dry year in the Northwest, is it fair to blame the waters of the Pacific?  I say no!  In fact the latest data from last week shows we still have an extremely strong band of cool water running through the Pacific. The data also suggest the La Nina is getting stronger!  Hard to believe right!

Area of interest is the band of cool water between Australia and North America.  (Credit: NOAA)

For those of you who don't know the difference between an El Nino and La Nina see the two globes below.

The Upper globe shows an El Nino pattern and the lower globe shows a La Nina pattern.   (Credit: NOAA)

So why is it that with such a strong La Nina set up, we have yet to receive any of the sweet powder we have all been promised?  In short the the words of Cliff Mass "no one knows".  The best theory meteorologists have at this point is that it is all due to the Jet Stream and the location of the formation of low pressure systems.  In order to benefit from storm systems spawning in the Aleutian low, the jet stream must dip south placing the Northwest directly in line with a trough (trough=low pressure).  Instead storm generation for this year is occurring farther east than normal and is leaving us sitting on a ridge, high and dry. (Information taken from NOAA)     

High Pressure sitting on us once again.  (Credit: NOAA)

So what are these weather patterns doing for our local snowpack?  So far as of today, not much.  Sacajawea  in the Bridgers is sitting at 53% normal, Lone Mountain is at 79% normal, Brackett Creek in the Bridgers is at 54% normal and Shower Falls in Hyalite is at 82% normal (NRCS).  If this trend continues its going to be a rough summer for irrigators, water managers, and the forests.  Keep your fingers crossed, maybe the Weather Gods will help us out and bring some big late season storms.  Until then find me out back drinking Coronas and grilling enjoying this 50 degree winter day.  

Enjoy, 

Kyle

(PS: If your really into weather check out this blog - http://cliffmass.blogspot.com/)