June 20&21 - Summer solstice storm

Prologue: The SPADE forecasters had been waiting for this storm for at least a week when we noticed unimaginable amounts of precipitation on the long range GEM models. As the day got closer, the models still suggested large amounts of precipitation that at the time had a few of us a bit skeptical. 

Our team waited for the 12PM MDT GEM model runs which came out close to 6PM MDT and we made a 24 hour plan expecting precipitation to begin at 0100 MDT. We were a bit surprised when we checked the radar around 8:30 PM and saw the rapid speed of the storm to the North making its way towards Fortress.

Fortress team (which consisted of Juris, Charlie, André and Cécile) readied themselves for the early start and we left shortly after. ​Excitement and adrenaline was high, much like the first Calgary storm. We even had several laughs as we filmed a tour of our trailer. 

- Juris 

Nipika 

Unexpected deluge
​
Drove through extreme darkness and pouring rain en route to our site. Perhaps there was a tiny amount of solid precipitation mixed in with the rain at the very top of Sinclair Pass, a brief whispering of the start of a transition zone. Somehow, despite the difficulties associated with sliding a truck through a deluge, we managed to arrive on site a little bit early, settling into the fine art of tarp stretching that has been perfected over the last two months at Nipika. With a little tarp heaven at my disposal, I settled into my observations at 0700 UTC (0100 MDT). 

0700 to 1030 UTC:
I was on the first shift, filled with strange imaginings in the constant roar of rain on the tarp and on the roof of the trailer. This was the most ferocious rain that I have experienced at Nipika and I assigned it an intensity of 4. However, I have been informed that my view of precipitation has been Nipika-ized (diminished in relation to the real world). With the air temperature starting at around 7°C, solid precipitation offered us no respite from the constant downpour of rain. Along with my wild imaginings, the little HOBO tipping bucket kept me company, happily clicking away at me in the deluge. On several occasions I finally saw long-awaited bursts of northern lights, however this turned out to be my flashlight beam caught in the constant presence of rain particles and distant fog. At 04:30 MDT (10:30 UTC) just as dark blue was starting to creep across the landscape, I passed my observation sheets onto Jeremy and then passed out in the back of the truck. 

- Selina

1030 to 1330 UTC:
I arose from a short but restful sleep in the bed of the research truck to heavy and sustained downpours which began to taper off over the duration of my shift. At first glance, the rain drops were an estimated 5 mm diameter during the heavier periods. By the time dawn had passed, the storm had lessened in intensity to a consistent light - moderate rain with roughly 2.5 mm raindrops or smaller. This rain was fully continuous for the duration of my first shift, and the tipping bucket gauge could be heard periodically dumping out its 0.2 mm increments of accumulation. By 1330 UTC, I was grateful to be done my shift, as I was more than ready to go back to sleep.

- Jeremy

1330 to 1900 UTC:
I reluctantly dragged my warm body out from my sleeping bag perched in a pile of sopping wet clothing and hauled myself into the trailer for my 13:30 UTC (07:30 MDT) shift. While my body felt like the rocks and gravel beneath the weight of the Kootenay River in full flood, my spirits soared during my shift, because, like always at Nipika, our best forecasters, the birds,  presented us with beautiful songs for the end of the storm. This shift was a relatively calm one, as gentle steady rain, transformed into drizzle, and then into the occasional drip that has haunted so many of our observations at Nipika. Unfortunately, this type of intermittent precipitation leaves you wondering whether you have actually encountered rain, or pee from a passing bird. Starting around noon, the precipitation came to an end (after a whopping 19.5 mm over the course of twelve hours), and the sun started to worm its way out of the thick layer of fog that had hidden the mountains and obscured the sky for the duration of our observations. I crawled into my sleeping bag shortly after 1900 UTC (1300 MDT) beneath gentle winds and blue skies.

​I awoke to blissfully warm sunlight and a dry truck, a completely different world from the night before. Thankfully the gum stuck to the top of my head brought me back to reality.  Apparently, my hat had seemed like a reasonable place to store it the night before.

- Selina

1900 to 2300 UTC:
My second round of observations were far more comfortable as the rain had abated, and temperatures had risen with the day and the breaking clouds. Observations were primarily of the shifting coverage of cumuloform clouds above, and noting heights of cloud ceiling and fog levels on the surrounding mountains. The winds were generally light from the south and southwest, with periodic gusty periods. I was grateful for the change to sit in the occasional patch of sunlight to dry out from the evening prior.

- Jeremy

2300 to 0000 UTC:
Light convective gusts and blue skies characterized my observations between 2300 UTC and 0000 UTC (1700 MDT and 1800 MDT), the last observations of the day. Unfortunately, the same delightful winds that were chewing away at the last vestiges of fog that still clung to the mountains, and helping the little cumulus clouds along, knocked over a tarp board and smashed Jeremy's ukelele into several pieces. After the usual array of cheesy photo-ops with the instruments and some data downloads, we sailed off into a bright warm evening.

-Selina

Field Participants: Selina Mitchell & Jeremy Morris

Fortress

Rainfall warning
 
0330 to 0530 UTC: 
Juris and I left BGI in a rush as soon as we saw how quick the big cell was moving over the north of Calgary. We arrived on site and took the first observation at 0330 UTC, and Cécile and André joined us about 30 minutes later. We observed a transition on the way up about 20 meters below the site elevation. The snow intensity was light at the beginning and increased in the first two hours. The wind was calm, the temperatures around 1°C and the hydrometeors were mostly aggregates of variable sizes and were melting really quickly if they were not already partially melted when they fell on the ground.

- Charlie

​Various snow types were observed from 0530-0730 UTC with large aggregates, measured up to 4 cm, though it looked like larger ones occurred watching out the window. Precipitation observations switched nearly every 10 minutes, and the degree of riming also varied. Precipitation started unrimed and then switched to heavy riming around 0620. Perfect snowball weather! At 0600 UTC snow depth was recorded at 5 cm with a SWE of 5 mm and at 0700 UTC snow depth was 10 cm with a SWE of 10 mm. Precipitation intensity ramped up starting at 0710 UTC. 

- Juris

0730 to 0930 UTC:
After working very hard on producing a beautiful video presenting our wonderful shared house (that you will be able to find on Youtube very soon), and while Juris and Charlie were taking on the first shifts, André & I tried to get some sleep on the tables in the lodge, as presented in the pictures. As weird as it may sound it wasn't that uncomfortable, but it was still tricky to fall asleep as we forgot to ask Mel how to turn the light off... So when I got off of table at 0720 UTC to take over my first shift I was already pretty tired. But seeing a strong fog, an intensity of snow about 5/5, very large aggregates and a consequent relative snowpack got me to instantly wake up and get very excited about my observations. The 2 hour shift then passed very quickly. The wind remained surprisingly very calm, and the snow intensity very strong for the whole duration of my shift. I was able to take macrophotographs at each timestep, and observe different types of particles, from heavily rimed dendrites to large aggregates, passing by needles, columns and plates.

- Cécile

0930 to 1130 UTC:
This period of the storm was very intense, with snowfall varying between intensity 4 and 5, and decreasing to 3 and 2 when it turned into mixed precipitation. Hydrometeors were mostly heavily rimed dendrites, aggregates, irregular-shaped hydrometeors, graupels, with some occasional occurrence of rimed columns. During mixed precipitation hydrometeors were marked by graupel and rain drops. Although the weather was stormy, the winds were calm to moderate. Also, during this period it was possible to see on the radar how the foothills of the Canadian Rockies were blocking this event, pouring most of the precipitation East of us, however, we still got a very substantial accumulation of snow on the ground (19.5 cm until 1100 UTC).

- André

1130 to 1330 UTC: 
Mixed precipitation of variable ratio occurred until 1200, after which the particles were only solid and heavily rimed, mostly graupel. Even with the calm wind, the snow intensity was a bit more than moderate. Temperatures a bit over 0°C, the snow didn’t accumulate on the board for that period, it stayed at 19 cm but the SWE went over 30 mm!

- Charlie

1340 to 1530 UTC:
​Precipitation started with heavily rimed dendrites. Winds were calm and then gusty coming from the NW at 1410 UTC. Strathmore showed a line of precipitation making its way to Fortress, but strongest precipitation diverts slightly south of us (23-45 dBZ). Temperatures were above 0°C and most particles looked partially melted during observations. At 1450 UTC mixed precipitation occurred.

-Juris

1530 to 1730 UTC:
After a 5 hour beauty sleep in the lodge, that left me as refreshed as the Kootenay river during its coldest days of May, I bravely walked through a deep snowpack that had doubled during my break, to get to our now famous trailer. However my second shift was very different from the first one, as the precipitation intensity was now moderate, and as I only got mixed precipitation in the first part, generally with a snow ratio of about 5% only, and only rain in the second part. That being said I wasn't able to take any pictures, so you will have to blindly trust my observations. The fog was still intense but the site remained pretty clear during these 2 hours. On the picture I took at 1700 UTC, you can see very clearly the base of the cloud that passed over us at that time.

- Cécile

1730 to 1930 UTC:
This period was marked by an alternating presence of mixed precipitation and solely rainfall. Intensity was very light to moderate, and solid hydrometeors when present were composed of small ice crystals, irregular-shaped hydrometeors, aggregates that broke and melted instantly upon contact with the velvet pad, and partially melted dendrites. By this time of the event, Fortress Mountain was in the fringe of the storm, thus light intensity precipitation was prevailing.

- André

​2040 to 2130 UTC:
My shift started off very foggy and shifted throughout the hour with varying degrees of "fogginess". Winds were calm for the majority of the hour but from 2100 to 2020 UTC winds were generally northerly. At 2110 mixed precipitation (70% rain and 30% snow) consisting of partially melted graupel and rain was observed at the same time as the fog rolled in swiftly.

- Juris

2130 to 2230 UTC:
For my last shift, I sadly didn't get any precipitation, and moreover had to observe the snowpack gradually melting... But I suddenly realized that the observations I was taking at that time were maybe the last ones I would take for that project, so I tried to enjoy them as much as I could. This storm might be the last one to be part of the project SPADE, but it was definitely not the least!

- Cécile

Field Participants: Charlie Hébert-Pinard, Cécile Carton, André Bertoncini & Juris Almonte

Nipika

Fortress