Thursday, February 14, 2019

A Relaxing Commute to Work

We've now been in Austria for almost a month.  During that time, I have not driven a car, although I have ridden in one three times when going skiing with friends.  If I lived here permanently, I'd probably want one, mainly for accessing skiing, but it's pretty easy living without one in Innsbruck.  The public transit is quite good and unless the weather is bad, walking is a lot of fun given the beautiful mountains in all directions. 

My "commute" to work involves about a 10 minute walk, downhill to the office and uphill home, navigating four switchbacks (I throw that in just to make it sound like an adventure).  It probably took me 15 minutes today as I stoped to gape at the mountains frequently.  Below are a few photos I took, one just below our apartment, the others where I cross the Inn River. 






As you can tell from the blue skies, the Steenburgh effect is in full force right now.  It continues to snow in Utah, and a huge block is setting up over Europe.  Coincidence?  I think not.

Tuesday, February 12, 2019

Western Austria Snow and Avalanche Information

I've been in Austria for almost a month and thanks to a little help from my friends, especially Lukas Lehner here at the University of Innsbruck, I'm finally beginning to get a handle where to find weather, snow, and avalanche information.  I'm interested in a lot more than the avalanche report, but also mountain snow and weather observations, and there are multiple sources for those. 

In part, the complexity of finding all this information reflects the jurisdiction of European countries and Austrian States.  I will focus today on western Austria, which includes the Tirol and Voralberg. 

Source: WIkipedia
Tirol is the German spelling and I will use that here.  Curiously, the Tirol is divided into two pieces, despite it being one state.  As I understand it, this is an artifact of the World War I armistice, which ceded the Südtirol (South Tirol) immediately south of the Alpine divide to Italy. 

Multilingual avalanche forecasts and information for the Tirol, Südtirol, and Trentino are available at https://avalanche.report

Source: https://avalanche.report
I've found this to be an excellent source of information, and they provide access to high-resolution weather and snow analyses produced for the Tirol by ZAMG, the Austrian Weather Service.  These include analyses of snow height (sometimes called snow depth in the U.S.) and fresh snow.  Below is an analysis for this morning.  The contrast from north to south is apparent with the deepest snowpacks in the mountains north of the Inn Valley including immediately north of Innsbruck and in the Arlberg region in the northwestern part of the analysis.  One can also access observations from some observing sites. 

Source: https://avalanche.report
Further west, avalanche forecasts and information is also available for Voralberg, the westernmost Austrian state, at https://warnung.vorarlberg.at/vtgdb/dist/index.html#//lwd/lagebericht.html.  This site focuses on risks other than avalanches, but does provide access to some snow and weather observations in the region.

Source: https://warnung.vorarlberg.at/vtgdb/dist/index.html#//lwd/lagebericht.html

Those sites are very useful, but other sites provide access to more data or analyses in alternative formats.  ZAMG provides analyses from their INCA model at https://www.zamg.ac.at/incaanalyse/.  This allows one to get a broader perspective on the Austrian Alps and, at least this winter, the remarkable snowpack that exists throughout the northern Alps. 

Source: https://www.zamg.ac.at/incaanalyse/
Snow and weather observations are available from several sites.  I don't know if there is any one site that integrates this information like MesoWest does with weather data in the U.S.  For the Tirol, one option is Hydro Online (maybe start at https://apps.tirol.gv.at/hydro/#/Schneeh%C3%B6he/?station=101501).  An example of a snow height graphic for the season, displayed relative to data from the period of record, is provided below.  This site is in near the German border at 1670 in the Lech Valley.  Snow depths are near the highest in the period of record, although there must have been a huge storm cycle there one year that pushed them to a full 5.5 meters in late February.  Click on the Schneehöhe Jahr tab if you go to the link to see the annual trend. 

Source: https://apps.tirol.gv.at/hydro/#/Schneeh%C3%B6he/?station=101501
Another option is https://www.lawis.at/station/. Below is the seasons observations from the same site presented above.  They provide a very nice interface with detailed topographic maps.  The site is the red dot in the image below, so you can get some perspective on the characteristics of the site.  

Source: https://www.lawis.at/station/
One thing that I've found challenging is that the border between Tirol and Voralberg lies in Arlberg pass and the Arlberg region, which I like to look at because it is one of the snowiest regions in Austria.  As a result, I find myself switching from site to site quite a bit.  

By and large, there is a remarkable amount of data to play with, which is really great given the incredible spatial variability in weather and snow that exists in the Alps.  

Monday, February 11, 2019

Textbook Alpine Meteorology

For a synoptic and mesoscale meteorologist like myself, the past 24-hours have provided just what I have been looking for on sabbatical leave: An education in Alpine meteorology.  

We begin at 1200 UTC (1300 CET) yesterday when an Atlantic cold front was sweeping across northern Europe and beginning to impinge on the western Alps.  I have annotated a summary of the situation on the 850 mb (1500 m) wind and temperature analysis below.  With southwesterly flow ahead of the front and associated trough, locally warm conditions predominated in the northern Alps and adjoining lowlands.  This reflects the influence of the Foehn (see also the previous post), a warm, downslope flow that develops during periods of large-scale southerly and southeasterly flow. 


The situation began to change quickly by 1800 UTC (1900 CET) as the cold front pushing into the western Alps, bringing with it cooler air from the northwest and a cessation of the Foehn.  At this time, the warmest 850-mb air was confined to the northwest Alps and lowlands to the north where it had been transported to in the southwesterly flow.  Note also the deceleration and splitting of the flow as it impinged on the western Alps.  This is also very common and it reflects the stability of the low-level airmass, which is unable to move unimpeded over the formidable Alpine topography. 


By 0000 UTC (0100 ECT) 11 February, cold air has encircled the western and the northern Alps.  There is a sharp contrast in temperatures across the Alps, which reflects both the stagnation of low-level cold air to the north and the development of downslope flow into northern Italy, where temperatures have increased from the previous two analyses.  Essentially, northern Italy is now experiencing Foehn conditions.  In addition, note how rapidly the cold front has pushed eatward across Austria, Slovenia, and Hungary, which is a result of the blocking of the flow by the Alps, which rotates the flow to more westerly and allows the front to accelerate eastward. 


And finally, the forecast for noon today shows cold air encircling the eastern Alps, downsloping the Dinaric Alps, and flowing over the Adriatic Sea. 


The satellite image from this morning shows the sharp contrast in weather across the Alps.  Note in particular the clear skies in the western Po Valley of Italy and the clouds banked up over the northern Alps and east of the Dinaric Alps.  

Source: https://en.sat24.com/en
European meteorologists have recognized these impacts of the Alps and other ranges for a long time.  Below is an analysis from the great Swedish meteorologist Tor Bergeron, published in 1928.  The flow is a bit more westerly, but you will see the similarities.  


That analysis has always been one of my old-school favorites. 

Sunday, February 10, 2019

Dodging the Foehn

After yesterdays splendid ski tour, I thought I would do a short day of alpine today (Sunday) and get a little work done in the afternoon.

There was, however, a challenge as today was forecast to be a Foehn day.  The Foehn is a strong downslope wind that affect the northern Alps during periods of southerly cross-barrier flow.  Think of it as the Alpine equivalent of Utah's "Canyon Winds", although they are more frequent.

Owing to the surrounding topography, Innsbruck is quite exposed to strong Foehn.  Innsbruck lies in the deep Inn Valley, which runs predominantly from west to east, with the Inn river flowing eastward.  Although surrounded by high mountains, the Wipp Valley lies due south of Innsbruck and represents a low-elevation corridor that connects with the Alpine Divide at Brenner Pass, where the border to Italy lies.

Map background source: maps-for-free.com
During Foehn, strong winds extend down the Wipp Valley to Innsbruck.  They also have a strong influence on the Patscherkofel, the easiest ski area to access from my apartment, as it is immediately adjacent to the Wipp Valley.

I'm not expert on the local meteorology around here, but enough people told me to avoid the Patscherkofel during Foehn that I never even considered going there this morning.  Instead, I went to Axamer Lizum, which is probably the best ski area I can access on a free bus anyway.

Turns out it was a good call.  Below is a seven-day time series of wind speed and gusts from the top of the Patscherkofel (these are provided by ZAMG, the Austrian Weather Service).   Southerly flow at this location began late yesterday (1800 LST) and ramped up overnight and today.  So far, the peak gust of just over 120 km/hour (75 mph) was at noon.

Source: ZAMG
The Patscherkofel gondola doesn't reach the summit where those observations are taken, but I noticed as soon as I got back to Innsbruck that the bus stop for the line going to the Patscherkofel ski area said the gondola was closed due to the weather.  Yes, they provide that information on electronic signs at the bus stops.

Meanwhile, in Innsbruck at the University of Innsbruck, winds really picked up after noon, with a peak gust of just over 75 km/hour (45 mph).  The local flow there is westerly, although the origin of the winds is the south.

Source: ZAMG
I had no problem skiing at Axamer Lizum this morning.  The timing was good (before the flow really ramped up) and it was less exposed than the Patscherkofel.  I was, however, able to observe some of the effects of the Foehn.  The Panorama below is taken looking toward the ENE.  Innsbruck lies in the deep valley at left and the flow is mainly from right to left.  To the right of the prominent peak just lef of center, one can see low clouds that have spilled across Brenner Pass into the Wipp Valley.  These clouds eventually dissipate as the flow descends into the Inn Valley, warms, and dries.  However, there is a band of clouds over the Nordkette range immediately north of Innsbruck.  These clouds persisted all morning and they were the only clouds along that entire range, including its extension further west, which can't be seen in the photo.  I suspect that the Foehn winds were riding abruptly on the south face of the Nordkette, leading to the cloud formation either due to that area seeing the strongest incident flow and/or the flow from the Wipp Valley being a bit cooler and moister since it traversed a lower portion of the Alpine Divide (i.e., Brenner Pass and the immediate surrounding area).  My colleagues can correct this hypothesis tomorrow if it is wrong :-).  


Getting back to skiing, I rode the chair today that ascends the Bergitzköpfl, which services ungroomed terrain on the east side of the valley and provides a view of most the terrain at Axamer Lizum.  One can see the funicular snaking to the top and several chairlifts.    


Although the light was terrible when I took those photos, the filtered sun provided good light for most of the morning, with no major impacts of the Foehn, although I did noticed that they cancelled their hot air balloon event.  

Saturday, February 9, 2019

Tirolean Backcountry Adventures

Since arriving in Innsbruck, I've been able to do some touring up the resorts but hadn't ventured into the Tirolean backcountry, so it was a real treat to be asked to join a group on a tour this weekend. Making the trip extra special was the group's international flavor, with people from France, Czech Republic, Croatia, Germany, and the United States.   

The Wasatch are having a great season with a deep snowpack in both the lower and upper elevations.  Ditto for the northern Alps (i.e., north of the Alpine divide).  Although we weren't touring in an area with an especially deep snowpack, we still found impressive coverage at the trail head. 


Our ascent covered about 1140 vertical meters.  As I have said many times since we arrived here, the Alps never disappoint on a clear day. 


There's terrain everywhere around here, but also many avid skiers.  We found a small crowd on the summit, although we didn't see many on the trek up or down and had plenty of room for turns. 


The U needs to get something out of my sabbatical.  Here it is.  Product placement at its finest.


There was good settled powder in some areas, sun-damage in others.  Plenty of good turns to be had.


Yes indeed there is a robust snowpack in the Alps.  These farm buildings were nearly fully buried. 


Every snow climate has its peculiarities.  A few days ago I saw evidence of a glide avalanche in the mountains above our apartment.  The area we were touring in had aspects on the south side of the compass and plenty of evidence of cracking and gliding along grassy surfaces. 


We saw some small slides on steeper grassy terrain along the access highway as well.  A good warning for warmer days ahead. 

Working the aspects allowed one to find some nice powder. 



The valley we were in is accessed by a narrow road.  There is a small ski area that is bisected by the road and serviced by a T-bar.  You don't see this every day, but the T-bar actually crosses the road.  The skier you see in the photo below is sliding on a thin layer of snow that's been spread across the highway.  Note the gate with the stop sign on it to prevent an auto-skier accident.  Someone in the shack to the right of the road pulls a rope and raises the stop sign when no skiers are coming to allow cars to pass.  Presumably someone shovels snow on the road from time to time to smooth it out after a few cars have passed. 


The heart and soul of skiing are alive and well in this part of the Tirol. 

Friday, February 8, 2019

Adapting to a New Climate

The climate of the Alps is considerably different than the Wasatch and I'm having fun learning and adapting to it.  

One thing that has struck me as how cloudy it is here in Innsbruck, at least since my arrival.  My posts have frequently featured pictures on clear days, but I assure you, there are periods when clouds prevail.  Often these clouds are stratus clouds, relatively low and confined to the cold pool within the Inn Valley as well as other low valleys in the region.  

Last night we had a weak trough passage, depicted using 500-mb height contours in the loop below.  Accompanying the trough were mid and high clouds, as can be seen in the satellite imagery.  


Also accompanying the trough were low-level clouds and moisture and, in the post-frontal environment, the view from my office this morning was overcast and grey.  


However, web cams above Innsbruck reveal a much nicer weather in the mountains, with undercast topping out at about 1000 m above sea level and just a few clouds at upper elevations. 


The photos above were taken around 8:30 am local time.  By 9:20, the clouds above mountaintop level had fully dissipated, but the clouds at upper-elevations were developing a bit more vertical extent as slope flows develop and the valley ventilates.    


I've seen this a couple of times since arriving here.  Most remarkable is how grey it can be in Innsbruck, with clear skies seemingly hundreds of miles away, when they are only a few hundred vertical meters.  The experience is similar to a Salt Lake Valley Inversion, without the pollution, but without the buildup or longevity.  Thankfully, with a high density of web cameras throughout the region, it is very easy to ascertain where to go or climb for better weather.