Wednesday, March 20, 2019

Bagging the Patscherkofel

Since we arrived in Innsbruck on January 16, I've been staring at the Patscherkofel from our dining room window (pictured below on our arrival day) and thinking it must be summited. 


As far as Alpine summits go, the Patcherkofel is a pretty insignificant peak.  It reaches only 2246 meters.  It's surrounded by higher terrain for the most part and doesn't get a lot of snow.  However, I have been skinning to the top of the ski resort once a week for most of the winter for exercise as it is easily accessed by bus.  With the winds light today (the summit can be very windy), I finally decided to extend my workout a couple hundred more vertical meters and bag the summit.  Plus I wanted to do it from the base and with the warm weather, it is unclear how much longer one will be able to skin the mountains lower slopes. 

There's really nothing adventurous about making the summit.  In fact, from the top of the ski resort at 1965 meters, they actually groom a route to the top. 


I got an early start before the lifts opened and was one of the first to reach the summit, but on my return, I passed many snow hikers who rode the gondola and then hiked the road to the summit.  This is an example of how the ski areas here encourage multiple uses of their facilities. 

I was also passed by someone getting a mechanical assist. 


Turns out there is a restaurant on the top.  The dude getting the pull was on the staff. 



There used to be a lift to the summit.  There was a sign on the wall commemorating its 50th anniversary.  They must have decided to take it out when they redid the lift system a few years ago, which makes some sense given the strong winds that frequent the summit. 


The Patscherkofel summit is not exactly pristine.  It is has some big infrastructure.  The tower below is a beast.  There was a 160 km/h (100 mph) wind gust a few weeks ago and it takes some serious steel and engineering if you're going to operate equipment like this in such an environment. 


My trip to the summit was not without work-related significance.  Below is a weather station operated by ZAMG, the Austrian weather service. 


A close up shows the precipitation gauge (white cylinder with black rim near center) is unshielded – meaning there's no attempt to break the wind near the gauge orifice, which often results in low measurement bias, as we discussed in my class here on Tuesday (students pay attention!).   


Also on the summit is a weather radar. 


There are numerous challenges to operating and interpreting radar from such a location.  One of the bigger ones is that the beam is well above the valley floor, which sits about 1500 meters below the Patscherkofel summit.  As a result, the radar often overshoots what is happening within the valley, although this can be addressed to some degree using negative elevation scans (i.e., at angles below the horizon).  Another topic discussed in class on Tuesday that my students can further ponder. 

There aren't many places in the world you can simultaneously see a ski tourer and a radome (the white sphere covering the radar), but the Patscherkofel is one of them. 


Views of Innsbruck and the Inn Valley were spectacular.  The clouds lingering along the south-facing slopes of the Nordkette on the far side of the valley likely reflect the influence of thermally driven upslope flow.  In contrast, it cleared out quickly this morning on the north slope of the Patscherkofel and over the center of the valley. 


Finally, to wrap things up, cloud cover overnight led to some impressive surface facets. 


I'd be worried about these for the next storm, but it's going to be unseasonably warm again as another ridge builds over the Alpine region.  These rascally facets won't last long.

Sunday, March 17, 2019

A Weekend in Obergurgl

This weekend we really scored in a number of ways.  Mother Nature blessed us with much needed snow on Friday.  She then provided clear skies for the weekend.  Finally, we got lucky and landed two nights at the University of Innsbruck's Obergurgl Conference Center in Obergurgl, which offers slopeside accommodations at a (somewhat) affordable price.

Obergurgl is located in the very upper reaches of the Ötztal (Ötz Valley), which is the longest valley that connects to the Inn Valley.  It's most famous ski area is probably Sölden.  Obergurgl and nearby Hochgurgl, which are connected by lifts sit at higher altitude (each near 2000 meters).


The surrounding Ötztal Alps represent one of the highest mountain regions of Austria, with numerous peaks exceeding 3000 meters, including the Wildspitze, Austria's second highest peak at 3770 meters.  As can be seen in the pictures further down in this post, it is a spectacular area, with deep valleys and big vertical.  Sölden, for example, has a lift served vertical drop of nearly 2000 vertical meters (6500 feet).

What the Ötztal Alps don't have is much powder.  Mean annual precipitation (inches) is pretty low in the Ötztal as they are buried deep in the heart of the Alps and most storms drop their load on lower terrain to the north and the south.  In fact, there is a dramatic decline in mean-annual precipitation and cool-season snowfall as you move from the Arlberg region in northwestern Austria, including Warth, Lech, and St. Anton, to the Ötztal, a fact that our bartender lamented yesterday evening when I was talking with him about the regional meteorology (never underestimate the meteorological knowledge of a ski-touring bartender).

Source: Steenburgh (2014)
Nevertheless, there were three things that attracted me to the area.  The first was beauty.  The second was the University Conference Center.  The third was the lack of a nightlife.  A beer or two with dinner and I'm good.

Obergurgl and Hochgurgl are two interconnected ski areas that are smaller and quieter than nearby Sölden and perhaps rate as medium sized Austrian ski areas.  Collectively they have 22 lifts, 110 km of pistes, and a 1289 meter (4230) foot vertical drop.  The lowest point is at 1793 meters and Obergurgl and Hochgurgl are at 1930 and 2150 meters, respectively, which is high by Austrian standards.  They are interconnected by a long, quasi-horizontal gondola that traverses a few deep valleys that would present a challenge for piste-type ski terrain.  



 The two villages are modest in size, but contain some large guesthouses (Top: Hochgurgl, Bottom: Obergurgl from the University Conference Center).



The ski areas have an abundance of intermediate terrain, with some steeper off piste skiing in some areas.  I found them to be a nice place to ski for a couple of sunny days.  The photos below provide some perspective.








The Obergurgl side has a bit more pitch, but Hochgurgl the longer runs.  It is possible to ski the full vertical on the Hochgurgl side, which I did once non-stop.  4000+ vertical feet is a long run anywhere, but it's not as difficult to manage as at Jackson Hole.  Mother Nature brought fresh snow on Friday and we arrived in a snowstorm.  Avalanche danger was high on Saturday, so I only did some nibbling in lower-angle off-piste terrain, but it was a warm storm and with a bit of wind, the snow was stiff and not great.

I mentioned views.  On a clear day, your mouth is agape continuously.  We had a run right after opening on Sunday morning at the easternmost edge of Hochgurgl that was the quintessential Alpine piste experience with nobody around, brilliant blue skies, perfect corduroy, and an unbelievable view down the Ötztal.

It can be crowded, but the Mountain Star at Hochgurgl is a fun place to visit.  The view below is walking to the Mountain Star from the top of the Wurmkoglebahn II quad chair, with the Ötztal Alps in the distance.


One can walk beyond the Mountain Star and in addition to seeing the Ötztal Alps (in the distance) you can also look down the Ötztal (to the right out of the picture) and into Italy (to the left out of the picture), the border to which is only a couple hundred meters away.


Below is the view into Italy with the Dolomites in the distance.  On this day (Sunday, the other pictures above are from Saturday), haze and low clouds were beginning to develop at lower elevations south of the Alpine Divide.


At Obergurgl, the top of the Hohe Mut Alm Gondola is the high point with the top "hutte" worth walking into just to check out the woodwork.


The peaks across the valley from Hohe Mut Alm are well over 3000 meters.  If you click on for full size, you might be able to check out the touring tracks in the center of the photo.


Finally, I mentioned the University Conference Facility.  What a spot above Obergurgl, right on a major trail.  Accommodations are basic, with breakfast and dinner served, which is a great option if you want to decompress.  I need to work on having a meeting here some day!





And, still my heart, there's a weather station!  Note that they do quite a bit of research up here, especially ecological.


 I close with a shot taken through the bus window looking up valley from the lower Ötztal on our way home.


The photo doesn't do it justice as this is spectacular country with big vertical that isn't as apparent through the camara lens.   I am looking forward to a return visit in the spring.  

Friday, March 15, 2019

Atmospheric River Conditions in the Alps

As anticipated in my post on Monday, atmospheric river conditions developed over the northern and western Alps Thursday night and continue today.  The GFS integrated vapor transport analysis produced by the Center for Western Weather and Water Extremes shows the atmospheric river curving anticyclonically from the north-central Atlantic, across the British Isles, and to the Alps. Note how water vapor depletion by precipitation fallout causes a rapid decrease in IVT across the Alps, but high values can sneak through the Rhone Gap between the Pyrenees and Alps and into the Mediterranean basin. 


The combination of abundant moisture and strong westerly flow between a high-pressure system off the coast of the Iberian Peninsula and a low-pressure system near Iceland generates relatively high integrated vapor transport values that appear to be near 1000 kg/m/s near the British Isles, but are perhaps closer to 600 near the Alps.  This, combined with the perhaps 1-2 day duration of the atmospheric river, would make it a weak-to-moderate atmospheric river event in the Alps based on the recently released scale designed by Ralph et al. (2019). 


The applicability of that scale for Europe is unclear, but I think that's a reasonable classification of the current conditions.

Overnight brought perhaps the most rain we've seen here since we arrived.  Prior to going to bed, it was raining very steadily.  This morning, it was raining lightly, with some opting for umbrellas. 


The mountains have been mainly obscured, but the snowline appears to be somewhere around 1000 meters or so. 


The atmospheric river is accompanied by a warm front, so this is a classic situation to produce heavy and "upside down" snow in the higher elevations.  Snowfall in western Austria over the past 24 hours has been fairly impressive with many reports of 40-50 cm.  This includes resorts near the Alpine Divide like Obergurgl-Hochgurgl that have been skunked in some of the colder northwesterly flow storms this year.   

Source: Bergfex.com
There are substantial numbers in portions of Switzerland as well. 

We are traveling to Obergurgl-Hochgurgl later today.  It could be an adventure.  After this snow, tomorrow looks sunny and warm, the former appreciated, but the latter is not.  I suspect there will be some big slides on south facing aspects and gloppy snow later in the day.  We'll be sticking to the piste.

Thursday, March 14, 2019

Visiting "ZAMG"

The Zentralanstalt für Meteorologie und Geodynamik (ZAMG), which translates to the Central Institute for Meteorology and Geodynamics, serves as Austrian Weather Service.  I had an opportunity to visit with the Tirol office today, which is located at the Innsbruck Airport.

ZAMG works for both the government and clients, and thus has a operations model that is fundamentally different from the National Weather Service in the United States.  In addition to national and state level forecasts and products, they provide tailored weather monitoring and products for a variety of customers.  Those customers include railroads, road maintenance groups, avalanche services, and alpinists (who they provide forecasts for around the world).  They even do weather monitoring and forecasting for the Hahnenkamm in Kitzbuhel.  Good work if you can get it.

One can access some of the products they produce on the web, such as highly detailed (1-km grid spacing) snow-depth analyses like the one below that is available at https://avalanche.report.   Readily apparent below is the much deeper snowpack this season in the northern Alps compared to the southern Alps.  Also evident are areas that have been strongly favored in this season's westerly to northerly flow snowfall events such as the Arlberg in the northwest part of the analysis domain and the Kawendel Alps north of Innsbruck.  


Interested in future snow?  They provide a variety of products such as the high-resolution 48-hour snowfall forecast below that is available from bergfex.com.  I chose 48 hours in this case as it fully covers the next storm which should end Friday night.  In this instance, the Arlberg region is once again favored, but even the Otztal Alps in southern Austria southwest of Innsbruck are supposed to get a decent dump, including 30-40 cm (12-16 inches) at an undisclosed location in the Otztal Alps where I'm spending my weekend.  


The office itself looks pretty similar to a U.S. National Weather Service Office with enough monitors that you should apply sunblock liberally.  


ZAMG also has a number of people who forecast on product development working primarily in Vienna, but also in Tirol.  I met one person who is working on implementing a new ensemble modeling system that will incorporate stochastic physics, an approach that is also being tested for implementation in the future HRRR ensemble in the U.S.  

By and large, a very impressive operation. 

Monday, March 11, 2019

Active Alpine Weather and Big News from Colorado and Vermont

There's much to talk about as I start my work week in Innsbruck as it looks like an active week in the Alps, which presents the opportunity to talk a little bit about European and Alpine meteorology. 

We'll focus on the forecast produced by the U.S. Global Forecast System since the ECMWF model is paywalled here just like it is in the U.S. (I have access to it, but can't share).  An upper-level trough will be passing across the Alps today and at 1200 UTC (1300 CET) is progged to extend from Germany to northern Italy. 


It was a beautiful partly sunny morning when I walked to work this morning at 0745 CET, but it's 0900 as I write this and change is afoot.  Images looking east down the Inn Valley from the top of my building show the overspreading of clouds and virga over a one-hour period. 



There postfrontal airmass is fairly unstable as a number of lightning strikes are being detected upstream over France, Germany, and Switzerland (not shown).  Northwesterly flow behind the trough will hopefully mean a good dump for favored locales like the Arlberg through this evening. 


After a break on Tuesday, another trough brings some action late Tuesday night and Wednesday.  Ahead of the upper-level trough, this one features westerly upper-level flow and cyclogenesis south of the Alps, which might bring some snow to the main Alpine divide. 


The action shifts to the northern Alps Wednesday night and Thursday as the trough exits and we transition into a so-called dirty-ridge scenario with moisture streaming toward the Alps from the west-northwest downstream of a low-amplitude ridge centered just off the west coast of Europe.  The forecast below is during the development of the wettest part of the period at 0000 UTC (0100 CET) Friday. 


The precipitable water and sea level pressure forecasts valid at 0000 UTC 15 March show the origins of the moisture plume, which likely qualifies as an atmospheric river, at least over the Atlantic.  First, a tropical moisture export occurs with high precipitable water air streaming northward between a low-pressure system over the central Atlantic and a high-pressure system centered off the coast of Portugal and Spain.  Strong confluence and moisture convergence between the westerly flow associated with a complex low pressure system over the North Atlantic and the high-pressure system centered off the coast of Portugal and Spain help maintain high precipitable water values as the moisture plume streams northeastward.  The moisture plume then moves anticyclonically across Ireland, England, and France toward the Alps. 



The result is a wet pattern for areas in the northern Alps and Alpine Foreland of Switzerland and Austria.  The GFS is advertising a maximum of just over 25 mm of precipitation (magenta color fill) in northeast Switzerland and western Austria for the 6-hour period ending 0600 UTC 15 March. 


The GFS does not adequately resolve the Alps and this is a 4-day forecast so we will have to see how things evolve.  I would expect snow levels will be rising with the atmospheric river and suspect we're going to see rain in the mountain valleys and an upside-down snowfall at upper-elevations with plenty of wind. 

In other news, you've probably been following the historic avalanche cycle in Colorado.  Ethan Greene, director of the Colorado Avalanche Information Center, commented last week that "it's pretty safe to say that nobody alive has seen a week like this."  Ethan is an University of Utah alum, distinguished alumnus of my department, and a good friend.  He choses his words carefully, so I take him at his word that this is indeed a remarkable avalanche cycle. 

Finally, congratulations to the University of Utah Ski Team on winning the NCAA National Championship in Vermont this weekend, their second in three years. 

Source: Utah Athletics