Bonneville Fire Meteorology

Yesterday (Sunday) morning in Innsbruck I woke to find a number of text and e-mail alerts concerning a wildfire near the University of Utah Campus.  As of 1000 CEDT here in Innsbruck and 0200 MDT in Salt Lake City, Utah Fire Info is reporting that the fire is human caused, has burned 495 acres, and is 5% contained.  Fire perimeter mapping shows the fire so far has burned between Dry Fork to the north and Red Butte Canyon to the south, including the Mount Van Cott summit and environs.  

Source: https://firms.modaps.eosdis.nasa.gov/usfs/map/

The fire was "discovered" on Saturday afternoon.  Two aspects of the meteorology that afternoon and evening likely affected fire spread.  As shown in the meteograms below from the Mountain Meteorology lab at the mouth of Red Butte Canyon, the relative humidity that afternoon was only 15%. During that period, the winds were relatively weak and variable, with directions mainly from the west to north, but at about 1930 MDT, the winds increased and became more consistently north to northeasterly.  The peak gust of 25 mph was at 2044 MDT.  Although temperatures lowered and relative humidity increased, the winds likely led to rapid fire spread.  

Source: https://mesowest.utah.edu/

The increase in winds was caused by outflow from convective storms in northern Utah.  Evaporative cooling from precipitation produced by these storms created cold pools that spread southward.  The leading edge of these cold pools is known as a "gust front" and is often is associated with a wind shift and rapid increase in wind speed.  Gust fronts are often dry, but can be detected in radar as a line of enhanced radar reflectivity, caused by greater concentrations of bugs and other non-meteorological targets, as was the case on Saturday.  

Radar image from 0040 UTC 21 July/1840 MDT Saturday 20 July. Radar image source: ral.ucar.edu.

A few hours after the strong winds produced by the gust front, the winds settled into a cycle that is typical of what happens near the University of Utah when there are relatively quiescent large-scale conditions.  At night, the flow becomes steady out of the northeast.  These are downslope and down valley (in the case of Red Butte Canyon) drainage winds.  The mountain meteorology lab probably observes some of the stronger winds in this area because it is at the mouth of Red Butte Canyon where there is a valley exit jet.  During the day, the flow becomes lighter and more variable, although the tendency is for the winds to initially become southwesterly to westerly in the late morning, consistent with upslope flow, and then shift to northerly with time as the larger-scale up valley flow in the Salt Lake Valley and the lake-breeze strengthen during the day.  These transitions are very apparent in the meteogram for the mountain meteorology lab.  

Meteogram source: mesowest.utah.edu

As I write this, it is nighttime in Salt Lake City, and one can see the predominant NE flow in the foothills around the University of Utah in the surface-map from roughly 0200 MDT Monday 22 June. The strongest winds are at the Mountain Meteorology Lab at the mouth of Red Butte Canyon and also near the mouth of Emigration Canyon.   

Source https://www.weather.gov/wrh/hazards

Forecasts for today (Monday) suggest such a wind cycle will predominate near the fire through Tuesday morning.  The NE flow will persist overnight tonight and into tomorrow morning, and then shift to southwesterly to westerly with surface heating as the upslope flow develops.  The HRRR forecast valid 1600 UTC (1000 MDT) Monday shows the development of W-SW winds near the fire area by mid morning.  Note though that there will be some fluctuation in wind direction during this light-wind period.

Then, in the afternoon, the winds veer to NW-N as indicated by the HRRR forecast valid 2100 UTC (1500 MST) Monday.  

Finally, Monday night, the NE drainage flow predominates, as illustrated by the HRRR forecast valid 0800 UTC (0200 MDT) Tuesday.  Note that the HRRR though cannot produce the local valley winds and exit jets (the background terrain in this plot is the actual terrain...the HRRR does not resolve the canyons in the Wasatch Range).  Adding such details is an important consideration for the incident meteorologists who may be working on the fire.  

From a wind perspective, this is a best-case scenario in the sense that these local flows are what you get when the large-scale flow is quiescent.  Whether or not we might see some flies in the ointment after today (Monday) is TBD.  There are a couple of weak troughs advertised by the models mid week that might provide some minor wrinkles and possibly a stronger trough over the weekend that could more strongly affect the fire-weather conditions.  Continue to monitor official forecasts and notices and hopefully fire crews can make progress on containment in the next couple of days.  

The Großglockner Hochalpenstraße

There are many great drives in the world, including some in Utah.  One that is surely on the list is the Großglockner Hochalpenstraße (Grossglockner High Alpine Road) in the Hohe Tauern National Park of Austria.  

The Grossglockner High Alpine Road is the highest surfaced road in Austria, reaching 2504 meters (8215 feet).  There is also a cobblestone spur road that will take you to the 2572 meter summit of the Edelweissspitze. We drove the road from north to south and then back in the same day.  It's not peak season here yet, so parking and pulloffs were not busy, but still the road was full of tourists (like us), bicycles, motorcycles, Porsches, and various "supercars."

The Grossglockner High Alpine Road was built in the 1930s and reminded me of the Going to the Sun Road in Glacier National Park and other National Park scenic roads in the US that were built in that same era.  It takes a sinuous route to and from the high altitudes.  

The Grossglockner High Alpine Road from Edelweißspitze

Our route took us first up the Fuscher Valley, a deep U-shaped valley with as much as 2400 meters of relief to the highest peaks.  Cascades and waterfalls tumble through green meadows.  It's very spectacular.

The higher elevations were more glaciated even only a few years ago.  Interpretive stops discussed ice falls from calving glaciers that no longer extend from flatter areas to the edge of steep terrain.  Austrian glaciers are not just retreating but disintegrating.  

After crossing two mountain passes, we began to descend into the Mölltal (Möll Valley).

Eventually we took a side road 8 km to the Kaiser Franz Josef viewpoint of the Grossglockner, Austria's highest peak (3798 meters).  Beneath the Grossglockner is the Sandersee, a glacier lake that began to form in the 1950s due to the melting of the Pasterze glacier.  Currently, the Pasterze glacier is Austria's largest glacier, but that may change soon.  There is a narrow neck, known as the Hufeisenbruch, that connects the upper and lower Pasterze (red circle).  That neck is narrowing and the Pasterze expected to split in two in the near future.  When that happens, it will be classified as two separate glaciers. 

The Kaiser Franz Josef viewpoint is beautiful but about as industrialized as you can imagine.  It has a massive parking garage and even a long tunnel that will take you through the mountain if you want to hike to the upper Pasterze.

Fortunately it wasn't very busy while we were there.  

Near the southern end of the road is the mountain village of Heiligenblut.  If you go to the right place, you can find a quintessential view of their church and the Grossglockner.  

The Grossglockner High Alpine Road is a toll road and for a vehicle it is 46 euro for day pass.  It's a touch cheaper for a motorcycle and completely free for a bicycle, although accident insurance is recommended and costs 4 euro (mountain rescue in Austria can be costly).  

One tip is to stay at a hotel or guesthouse that is a partner with the National Park Summer Card.  THe summer card gives you a free day of access to the Grossglockner High Alpine Road and you can get free access to one of the sixty attractions included in it each day.  For example, one day we visited the Krimml Waterfalls and other day we used the Rudolfhutte cable cars for hiking.  Such cards are common in the Alps and worth looking into.  For this trip, we rented a car (it was my first time driving in over 3 months!), but for others, such visitor cards often provide free transit access.  

Visiting the Rudolfshütte

A couple of years ago I saw an article in the quarterly newsletter of the Austrian Alpine Club (Österreichischen Alpenverein) about a mountain hotel known as the Rudolfshütte.  The hotel is only accessible via foot or cable car and is at an elevation of 2300 meters.  In the winter, it serves as the center of a ski area.  In the summer, as a center for hiking and mountaineering.  In the article, the photo of the Rudolfshütte was so attractive I swore a vow to visit.  I'm not sure if the photo below, which I snagged from the Austrian Alpine Club web site is the same as was run in the quarterly newsletter, but it illustrates the allure.  

Source: Austrian Alpine Club

We visited the Rudolfshütte today and, as it turns out, we got a real history lesson in addition to mountain views. 

Accessing the cable car to get to the Rudolfshütte involves a drive up the Stubach Valley, which ascends into Austria's Hohe Tauern National Park from Uttendorf, a village in the Pinzgau region.  This road is barely a two lanes, with many switchbacks.  The photo below sadly doesn't do it justice as it makes the road look much wider than it really is.  I kept thinking who the hell would build a ski area out in the middle of nowhere with the only access up a long and winding road like this?  

Then we got to the base of the resort.  Instead of there being a quaint Austrian mountain village, the place was very industrial.  

I learned latter that the Rudofshütte and associated ski area (apparently known as the Weißsee Glacier World) are located at the head of the Stubach Valley, one of the most important for hydropower generation in all of Austria.  There are multiple reservoirs, operated by the Austrian Federal Railways (OBB) for the purposes of electric power generation.  In fact, 20% of the power needed by the railways is generated solely from this valley.  

Then we located the ski resort and cable car, which was a bit of a museum piece.  It was built in 1982!  It must have been a remarkable lift at the time as it was detachable, but I have to admit getting on it in 2026 took a bit of courage. 

Our original plan was to take the two-stage gondola to the Rudolfshütte and do a hike to about 3000 meters, but web cams showed substantial snow cover at that elevation so we went to the middle station an hiked to the Rudolfshütte from there.  It was a cloudy day, but great views were still to be had and we got an introduction to the incredible hydrologic infrastructure operated by OBB in the valley.  

Eventually we arrived at the Rudolfshütte (building to the left in the photo below), which sits above the Weißsee (white lake) reservoir.  

At this point, my head was really spinning.  This is a 200+ bed hotel up at high altitude.  The hiking season is short.  The ski area is hard to access and is a relic from a time forgot.  So I started to do some digging and asked the operator of the guest house we are staying in for a little background.  She gave me a pamphlet that summarizes the history of the hut and ski area.  

The original Rudolfshütte was built in 1874 by what was then the German and Austrian Alpine club.  It really was a hut.  It had two rooms and five mattresses.  In the late 1800s, the development of rail from Salzburg made interest in travel to the Rudolfshütte attractive for tourism.  Rail access would have been to Uttendorf, 17 km away as the crow flies and 27 km by road plus two cable car stages today.  From there to Rudofshütte must have been a hell of an adventure back then.  Nevertheless, enough people visited to warrant expansion to a facility that could house 60 people.  

The road to what is now the base of the cable car was built in 1926, motivated in large part by the need for building hydro power plants.  This enabled for car or bus access to within about a 2.5 hour hike of the Rudolfshütte.  That's 2.5 hours for Austrians.  Probably more like 3 or 4 hours for most of the rest of humanity.  Spring skiing, presumably human powered, also became popular prior to World War II. 

The original Rudolfshütte was located closer to (or maybe under) what is currently the Weißsee reservoir.  That reservoir was built by the Nazis during World War II using forced labor, including prisoners from the Dachau concentration camp who according to the translated documents I have experienced "unspeakable suffering."  The first "ropeways" were built to the Rudolfshütte area during that dark time. 

After World War II the Rudolfshütte was relocated to its present site and it became widely used.  By 1957, the cable car, now operated by OBB, transported 100,000 tourists and the Rudofshütte was a training center for the US Army and Austrian skiers, including Toni Sailer and Pepi Stiegler, both Olympic gold medalists.

It appears that the gondola we rode today was built in 1982.  That was probably a time of great excitement, but the area has subsequently fallen on harder times.  As said in some of the materials I was given, "the economic expectation of the [Austrian] Alpine Club and those of the cable car operators were not fulfilled."  

Currently the Rudolfshütte is owned by an Austrian Hotelier named Wilfried Holleis, who was born in nearby Zell am See.  Holleis has been pushing for controversial expansion of the Rudolfshütte, which was recently approved.  A November 2025 article in the Kronen Zeitung reports:

"According to the hotel, there are too few day skiers. 'This is the only way the hotel and the ski area have a future,' reports a spokesperson for hotelier Wilfried Holleis. The long journey through the valley deters day visitors. Therefore, they are dependent on hotel guests who stay for several nights and use the lifts. The lift facilities alone have been operating at a loss for a long time."

Who knows what the future lies for this unique hotel and ski area, but I appreciate the opportunity to experience it today as it is a fascinating piece of Austrian mountaineering and ski history. 

See https://www.gletscherwelt-weissee.at/fileadmin/content-weissee/Prospekte/RH/Chronik_Rudolfshuette.pdf for more about the history of the Rudolfshütte. 

Glacial Past of the Alps

Our time in Innsbruck is winding down and we are taking a couple of short trips in the Alps before returning to Utah.  We are currently in the Hohe Tauern National Park, an area of Austria I've never visited before.  We arrived today and spent some time visiting the very touristy but also very beautiful Krimml Waterfalls. 

There was a information exhibit at the base of the waterfalls (collectively they drop over 1200 vertical feet) that examined water in all it's forms, including ice and glaciers.  At it, I learned of some remarkable modeling work by Julien Seguinot and coauthors simulating the glacial history of the Alps over the last 120,000 years.  The video is simply mind boggling.  

It's difficult to comprehend a past in which the Alps were essentially entirely ice covered and glaciers were extending into the Alpine Foreland to the north and south of this remarkable mountain chain.  Below is a the simulated reconstruction for about 30,000 years ago showing such a situation.  The color fill is the simulated glacier surface velocity, so those glaciers issuing into the lowlands at the flanks of the Alps were moving fast and quite dynamic.  

All I can say is science is cool, especially cryospheric science (the study of the frozen water part of the Earth system)!  

El Niño Update

The Climate Prediction Center (CPC) issued their June El Niño/Southern Oscillation (ENSO) discussion today (June 11) and it's almost certain to send some people into a tizzy, although those of us in Utah should be cautious about what to expect this coming winter.  

Before diving in, let's first talk about what ENSO and El Niño are.  ENSO is a natural cycle in atmospheric and oceanic conditions in the tropical Pacific characterized by a two to seven year cycle between warm phases (El Niño) in which the easterly trade winds weaken and the central and/or eastern tropical Pacific becomes anomalously warm and cold phases (La Niña) in which the easterly trade winds strengthen and the central and/or eastern tropical Pacific becomes anomalously cold.  

Various indices exist to illustrate the phase (and strength) of ENSO.  None of these is perfect since you are boiling down a complex ocean and atmosphere system to a single number.  I tend to favor the multivariate ENSO index or MEI.  Going back to 1979, the MEI has fluctuated between about -2.5 and 3.  Values greater than one indicate moderate to strong El Niño conditions.  Values less than one indicate moderate to strong La Niña conditions.  Two of the strongest El Niño events since the start of the 20th century are evident below: 1982-83 and 1997-98.  The 1925-26 El Niño is also in there amongst the strongest El Niños since 1900.  

Source: https://psl.noaa.gov/enso/mei/

As summarized in the CPC discussion, El Niño conditions, characterized by above-average sea-surface temperatures (SSTs) in the central and eastern equatorial Pacific, over the past month.  The figure below shows the departure of sea-surface temperatures from average for the week centered on 3 June and illustrates the anamalously warm SST not only in the central and equatorial Pacific, but also along the South American coast (as is often the case during El Niño).   

Source: CPC

There has been a lot of talk in the media about this being a "super" El Niño.  CPC doesn't use such flamboyant language, and in their May update they were very careful not to heavily weight the possibility of a strong El Niño, but in this June update they say the odds are stacked for a strong one:

"There is a 63% chance of a very strong El Niño during November-January [Fig. 8] that would rank among the largest El Niño events in the historical record going back to 1950."

So a very strong El Niño is not a lock, but is more likely than not.  At this lead time, that's probably the strongest confidence you are likely to see from CPC about a very strong event.  

However, and this is important for Utah skiers to consider, they also add the caveat:

"Even very strong El Niño events do not lead to the expected impact everywhere, but stronger events can more significantly tilt the odds in favor of expected outcomes."

And what are those expected outcomes?   For December-February Precipitation, CPC indicates greater than average odds for above normal precipitation across mos of the southern US including the southwest and below normal precipitation in the northwest interior.  As is often the case, there's no strong weighting for northern Utah.  

Source: CPC

One of the reasons for this is that there has been a lot of variability in precipitation in December to February during strong El Niño events. Below are postage stamps of precipitation during strong El Niño events so look for yourself.  

Source: CPC

I expect a lot of talk about what happened during 1982/83 and 1997/98 since those are the two strongest El Niño events.  Both of those events produced above average and very significant precipitation in California, the Wasatch, and Arizona.  At issue is whether or not those two "very strong" events are a reasonable sample or if the range of strong El Niño events that includes those and other events that were not quite as strong is a more reasonable representation of the range of possibilities.  As winter approaches, perhaps numerical seasonal forecasts will also have something to say, but I'm inclined to say that what will happen with precipitation this coming December to February is still up in the air.  There's no loading of the dice yet.  

That said, there is some loading of the dice that December to February will be warmer than average.  

Source CPC

That doesn't necessarily mean a repeat of last season.  A lot will depend on storm characteristics that we cannot anticipate this far in advance.  

Keep calm and carry on.  

The End Is Nigh

 The seasonal snowpack at Alta is nearly gone as indicated by yesterday's Mt. Baldy web cam

Source: https://www.alta.com/weather

and observations from Alta-Collins which indicate a total snow depth of 8 inches. 

Automated snow depth observations are such that the instrument might still suggest a few inches of snow on the ground when there is none.  That said, the end is nigh even with the overnight frontal passage, which might only delay the inevitable a day or two. 

Meanwhile, in the Alps, it is snowing at upper elevations!

Source: https://www.foto-webcam.eu/webcam/zugspitze/