Storm Thoughts – January 13, 2016

Snowfall totals as of 8:00am, January 13:

  • Pinkham Notch 7-8″
  • Hermit Lake 7.5″
  • Mt. Washington Summit 6.1″

For more locations, the NWS publishes a public information statement spotter report or take a look at CoCoRaHS. I had a little more than 5″ at my home in Conway this morning.

It’s been a lackluster start to the winter of 2015-2016, but last night’s snowfall certainly was good to brighten one’s spirits. Tuckerman and Huntington Ravines are currently posted under a General Bulletin and will likely remain this way at least for now. As long as I’ve been working here, I can’t remember a season that has started off so slowly. We’ve had our share of late starts and early winter rain and thaw events, but this had been remarkable.

As you can see in the photo, Tuckerman’s headwall had very little snow on it before the latest rain. Look closely and you might see a very small crown line in the Chute. This is the type of problem that can often be found even when we are posting only a General Bulletin – it’s a relatively small and isolated patch of snow compared to the hazards presented by the Chute with better coverage. In these conditions, you might find several patches of unstable snow if you go looking hard enough, but it’s not enough to warrant going into full avalanche forecasting operations.

Left side of Tuckerman, January 8, 2016

Left side of Tuckerman, January 8, 2016

This photo was taken on Friday, January 8. Two days later, Sunday, we got hit with a warm rain event with 1.4″ of melted precipitation and summit temperatures topping out at 35F. Needless to say, this impacted the already thin snowpack, leaving behind two ravines very hungry for snow.

Temperatures on Mt. Washington over the last week. Note the spike on Jan 10.

Temperatures on Mt. Washington over the last week. Note the spike on Jan 10. (Graph from NWS)

So what effect will this recent snowfall have? It’s certainly going to help, but given the prior snow deficit in the ravines, I think the overall effect on filling in the snowfields around the mountain will be minimal. Having said that, on a smaller scale there will be noticeable changes. It’s hard to ignore the forecast for increasing W and NW winds gusting over 100mph later today and tonight. These speeds will be effective in picking up any available snow from windward sides of the mountain and redistributing it into leeward sides.

If a more well-established base of snow existed in the ravines, with larger potential bed surfaces, this storm coupled with the wind forecast would pretty easily put us into Considerable or High avalanche danger. In fact, I could see this producing a pretty good natural avalanche cycle with multiple paths running. But the fact is that we are still establishing a base in the ravines, which changes the equation significantly and leads to a broad scale General Bulletin.

However, it’s important that we don’t fall into the trap of looking only at the big picture of this winter. Small snowfields can avalanche, regardless of whether we’re fully forecasting, under a General Bulletin, or even before the Snow Rangers start paying any attention at all. If I were looking to get out and recreate in these conditions, I’d be very suspicious of any areas of wind slab, no matter the size. I’d be thinking carefully about the consequences of a fall, knowing that even a very small avalanche can take me off my feet. It doesn’t matter if there isn’t enough snow to bury someone, what matters more right now is the bigger question of “what happens if…?”

I hope this doesn’t sound as if we’re talking out of both sides of our mouths. The fact is, we have conditions today that should be raising several red flags. Don’t be lulled into complacency by the overall lack of snow or the lack of an Avalanche Advisory. There is a lot of terrain you can cover in the mountains today and tomorrow that is not exposed to avalanche hazard (although with the weather and visibility, you’d do well to consider all available options), but it’s up to you to figure out where those locations are. We’ll be keeping tabs on conditions, and will begin forecasting as the snowfields grow larger and more capable of producing avalanches.

With a little help from Mother Nature, it might only be another couple storms like this and we’ll start to see the ravines looking more and more like their usual selves.

If you’re wondering about conditions on the Sherburne, the short answer is that I don’t yet know, but I can make some informed guesses:

  1. Let’s just be honest, for the better part of the past decade, the ski trail hasn’t seen the level of maintenance it needs. Fir growth in the upper third of the trail is pretty significant, meaning that until a deeper base is formed, the skiable track is only as wide as an ATV. Coincidentally, this is just about the same width as my snowboard. I found it very easy to catch a tip last week in the fir trees up high. (Contact us if you have a desire to help with this trail next summer.)
  2. While the trail was wet from Sunday’s thaw, someone apparently walked on the trail. These slushy footprints are now frozen into the base of the trail. (If you’re reading this and it was you…shame, shame on you!)
  3. The base was very thin and very hard prior to the rain, with many exposed rocks, sticks, and other hazards. The base now has much more water ice or icy snow, and more rocks exposed. Now we have 7-8″ of light density snow sitting on top of the ice. In many locations this will have been wiped clean by the wind. In a few locations you might be lucky enough to find a little drift.

Think snow!

Jeff Lane, Snow Ranger
Mount Washington Avalanche Center