What a busy weekend – I don’t think any of us have ever been so exhausted and excited! The upslope precipitation materialized and brought with it a lot of snow!
As mentioned in a previous blog post, we rushed on Friday to get supplies, finish setting up the site, and make sure that we knew how to work all the instruments. I (Hilary) stayed up at the site on Fortress so that I was available for measurements just in case precipitation came earlier than expected. The day started out beautifully and was really warm when the sun was out. Light snow started around 0000 UTC on April 27 (6 pm MDT) and tapered off shortly afterwards.
Mathieu & Juris arrived at this time, which gave me a well-deserved break. André arrived a few hours later. Snow occurred around 4 hours later than the forecast was predicting and it did not really pick up until the early evening, around 0310 UTC (9 pm MDT) and it was heavy with light winds for almost 2 hours. Particles were mostly small dendrites that were heavily rimed (pictured below). We anticipated a busy night, therefore we split into pairs with Hilary & Juris taking the 0400 UTC to 0800 UTC shift, while Mathieu & André rested underneath the tables in the trailer. During the first shift (Hilary & Juris) observed nearly 1 hour period of heavy snow which began as lightly rimed particles and as the precipitation became heavier, densely rimed aggregates were then observed. Often rimed dendrites and undistinguishable smaller rimed particles were observed. At 0600 UTC (0000 MDT) fog was present and made for very reduced visibility. Fog cleared shortly after 0900 UTC April 27 (0300 MDT) and the winds picked up significantly with strong gusts and resulted in blowing snow. Once the sun rose, Mathieu & Andre left Fortress to have a quick rest at BGI, while Juris & I stayed to make observations. During that time it was cloudy, with minimal snow, light winds, and fairly good visibility. Mathieu & André returned to Fortress to let Juris & I go to BGI to have a bit of a rest.
Snow began to fall around 2000 UTC (1400 MDT) at Fortress and became heavy quickly. Juris & Hilary left BGI around 2330 UTC (1730 MDT) when the snow became heavy to head back to Fortress. The highway to Fortress was pretty snow covered with poor visibility in some sections. We took over observations from Mathieu and Andre when we got back to Fortress. Snow was still very heavy. Over the course of the evening/night, we saw some very interesting particles such as capped columns, bullet rosettes, stellars, hollow columns, and various types of dendrites.
The snow ended around 1100 UTC on April 28 (0500 MDT) while Mathieu & André were sleeping. Juris & I went to hang out in the lounge. Snow depth was approximately 30 cm by the end of the storm. This meant that we were snowed in at the top! We backed up some data and hung around the lounge for a few hours before some trucks drove the road to the top and made a path for us to drive down. We took snow measurements every 100 m change in elevation on the way down and noticed a significant change in snow depth – from 30 cm at around 2100 m to 5 cm at 1600 m.
We returned safely to BGI for some much needed rest. All in all, it was a very exciting (and exhausting) weekend. A very big start to the project!
Field participants: André Bertoncini, Mathieu Lachapelle, Juris Almonte, & Hilary Smith