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Wind and mountain flying

TShort

Well Known Member
I'm hoping to get some insight (and perhaps some local knowledge from the CO guys).

My brother and I have a place in Buena Vista (KAEJ), and I fly the -10 in there a lot.

I've been cautious about learning to fly in the mountains, took the CO pilot's association course (ground and flight), and have spent the past couple years getting used to different aspects of mountain flying.

Thus far, all in the summer and fall.

I flew out today, and winds on the ground at midday were not conducive to flying into KAEJ. So I landed at KLMO.

My real question is how to approach the winds aloft. Winter winds seem to have arrived early this year. 30-40kt at 14,000' gives me pause. I am considering flying in early tomorrow AM. Surface winds will be fine, but I have no clue what to expect in terms of turbulence, the potential for wave / rotor, etc.

I'm fine with bumps. I tend to be cautious about things like this, and don't know if it is reasonable to go test the waters or not.

Anyone have any experience / thoughts?

Thanks in advance.
 
Hey Thomas -

I think there is probably enough data you can get out of some of the weather products around to be able to tell whether or not the wind will be a problem. Having 30-40kt winds isnt really an issue, its bumpiness and wind shear that will make for a not-so-fun flight.

I’ve really taken a liking to SKEW-T diagrams. Granted there are flaws in just about everything, but when I’ve used them, they’ve been pretty accurate in giving me a picture of what is going on in the atmosphere. You’ll be able to see how stable the air is and whether you have shifts in wind direction up there.

THey take a while to get used to, but once you learn how to use them, they’re extremely valuable.
 
Colorado Pilot Perspective

Others with mountain flying experience are invited to comment because more input is better in this situation.

The general rule around here (SW Colorado) and published in various places is not to fly in the mountains if ridge top winds, that is at 9000' and 12000', are forecast to exceed 30kts.

I personally get wary if they are over 20kts based on my experience, but definitely would not go if they were 30kts or above. Others may have different criteria, but all those with experience in mountain flying respect strong winds aloft at ridge top level. As noted, they can be obtained either via the standard winds aloft forecasts or the more sophisticated ones like the Skew-T or VAD wind profilers.

I cancelled a recreational flight this morning, on a perfect fall day, with calm surface winds, and CAVU to the moon. 9000' winds were 10kts, but 12000' winds were 37kts. There were SIGMETs out for occasional severe turbulence and moderate turbulence below 18000', and standing lenticular clouds were visible over the mountains from our house (elev 6000') in the direction of Buena Vista.

In general, there will always be at least AIRMETs for moderate turbulence in the mountains below 18000' when ridge top winds are in the 30 kt range.

My opinion is that you are to be commended on your decision making to stop at KLMO. For interesting reading, do an internet search about a tragic accident last week or so in Telluride where right after takeoff a Bonanza encountered a situation that resulted in impacting high terrain it could not clear.
 
jb-

Thanks for the input. My brother (who lives here in Golden) sent me the news article about the Bonanza, but I had not followed up to see the cause.

I'm still trying to decide if an early morning flight into KAEJ tomorrow is reasonable. I'm thinking maybe going high and coming across south park north of Pikes peak, going slow and seeing how the turbulence is.

I look at all kinds of data online, but at some point I need to get in the plane and see what all the numbers and lines translate into. I just want to do that safely.

Today, I was surprised at how calm and (relatively) smooth it was along the front range with 40+kt winds at 12-14000'. It was bumpy, but really just felt like a regular sunny / "thermally" day. I expected more bumps, but maybe the stuff coming off the mountains is higher (I came in at 6500' from KHLC). I know the airline guys talking to DEN center were complaining about the ride.

Good learning, keep the insights coming!

Thanks,
Thomas
 
Colorado Pilot Perspective

Based on my experience flying both airliners and light general aviation aircraft into all the Colo Front Range airports, from both the east over the plains and the west over the Rockies, what you experienced with relatively smooth air at 6500' would not be uncommon, but the turbulence would be expected to increase significantly, as you approached Front Range ridge level altitudes, say 8000'-12000' and above, under the winds aloft conditions you describe.

If airline crews were complaining descending into KDEN or KCOS, especially from the west, it would probably be quite uncomfortable in a light general aviation aircraft over the mountains. Again my view is that you made a good choice to stop in Longmont.

An alternative route would be over KPUB and up the Arkansas River Valley to Buena Vista. Longer, but generally more favorable terrain.

Enjoy your time in the Colorado fall weather.
 
Learn the general shape of the mountain wave effects. You can often see the lenticular clouds, not always, and sometimes you can see the rotor clouds. But the rotor is usually the one that'll give you a problem, assuming you don't get blown into the ground. It's rougher and more sudden, as well as being less predicable, than the wave effects associated with the lenticular.

I agree that 20 kts at 12,000 feet is a reasonable limit.

Certainly, take and use oxygen and an O2 monitor.

One simple approach to flying out here, if you have oxygen, is to loiter in the lift and skedaddle in sink. Just fly as fast as you can for the conditions (which could get worse!) and don't try to climb through it. Get out of it. Have a place where you can turn to that is at a lower elevation, if you need to.

Dave
 
All good info. I’m at KPSO and 20 miles from Wolf Creek Pass. Our field is at 7660. If winds aloft exceed 20 Kts it likely going to be a very bumpy ride. I have quite a bit of big helicopter time in the mountains and you need to be very careful in a little airplane. A lot depends on your altitude in ref to the ridge line and whether or not the winds are perpendicular to the ridge. Because these ridges are winding all over the place, it’s not that simple. You made the right decision. Hotels are cheap.
 
So I'm not quite half the pilot that some on here are, but I got my training in West TX. That said, winds aloft, who cares, winds on the ground, as long as they aren't gusting >15Kts more than the constant wind speed you should be fine. I'd say go get some decent crosswind training, and do a ton of landing/touch'n'go practice on the non-optimal runway on windy days, and you'll be fine in no time.

A little background, just due to how windy we are generally, we didn't consider it too windy for lessons until the X-Wind component was 20+kts.
 
Winds???

Just looked at the winds here on Dougs site. Could get questionable in mountains even earlier than forecast! If you go early and go down by Colorado Springs Then head in and north would be the safest. Do not be afraid to do a 180 and bug out if it gets questionable!!!
We have been getting a lot of gusty high winds for about the last few weeks. Some days smoth in the mornings, some days smoth for 1-2k AGL then goes to **** in a hurry!
I have about 1650 hrs mostly in Colorado's high country. Fly smart! You plan can change if you get into rougher air than you are expecting. 180 a pilots friend.
Best of luck, Hope you will tell us what you find tomorrow.
 
My advice is to know your personal limits (and your passengers' limits). Keep an eye on your maneuvering speed. Stay high to give yourself an out as necessary.

I was up this morning at +/- 11000 over the mountains near here (Delta-Montrose area) and it was windy and only a bit bumpy - but got worse as the morning went on. Always worse on the downwind side of the hill as well. Perfectly calm on the ground at KAJZ. If you can deal with the wind at altitude, often winds on the ground are ok.

My two cents.
 
That said, winds aloft, who cares, winds on the ground, as long as they aren't gusting >15Kts more than the constant wind speed you should be fine.

This is one of the BIG differences with mountain flying and, not to pick on the poster, is 180 degrees off. Surface wind, in the mountains, is the least accurate indicator of conditions up in the air. As others have said, the winds aloft forecast is your most important resource for VFR mountain flying. A couple of good rules of thumb, based on local knowledge, have been offered here - mine is 30kts at 18,000' (will result in a pretty rough flight). If it is hot, it will be even worse after the temp starts rising.

Of course, it depends on what you are doing. If an early flight doing pattern work or a local flight (staying in a valley or some such), you may be just fine. Thermal activity has not yet started and the mixing action of the winds aloft has not pushed the rough air down low. Another factor is airplane - wing loading to be more accurate. While my RV-4 is getting bounced around, a friend in his Glassair III is experiencing a very different ride.

Windy.com is another good resource as it displays how the air is moving at various altitudes - and the air is most definitely 'flowing' around mountains and thru valleys in interesting ways.
 
So I got up this AM and the Monarch pass station was reporting gusts to 48+, so I bailed again.

Now it is back to the mid to low 30's.

Does anyone have experience flying the Arkansas valley in similar winds?
The previous mention of coming up the valley from Pueblo is an option. However, I've flown that route several times and there is some pretty inhospitable terrain down south which I'd rather not fly low over. Just looking for PIREPS on what I might expect downwind of Princeton and the other peaks around there.

My current plan is to just leave the plane at KLMO, as windy.com seems to show pretty consistent winds up high for the next week. Which stinks, as I'd rather have it tucked in the hangar at KAEJ. Fortunately the weather looks good...
 
So I'm not quite half the pilot that some on here are, but I got my training in West TX. That said, winds aloft, who cares,

Umm...In mountain flying winds aloft are critical. Waves and rotors created by winds aloft >~25-30kt perpendicular to ridge tops can be deadly. Many mountain flyers do not fly when winds aloft are > 30kts and many less experienced pilots are smart to have limits of 20kts.
 
My personal limit is 20 knots reported at the peak or at first lowest forecast level above the peaks AND wind direction either down the valleys or at an angle no more than 45 deg. to the ridges. I will park it if the winds are perpendicular to the ridge.

This personal limit was set by my personal, ah, experience. I've experienced +3 -2.5 in rapid repeated succession, attitude excursions that included inverted over some very jagged peaks, items including a Ram mounted 796 gps smashed and (I assumed) secured O2 bottle fly around the cockpit & break the canopy. This in conditions forecast to not change to Lee Wave conditions for another 4 hours. I was in those conditions for over 15 minutes, didn't have to change my pants but sure felt like I needed to after that.

If conditions are questionable, park it & rent a car!
 
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Requested Colorado PIREP Downwind Of Mt Princeton

With the winds aloft conditions this morning the OP observed in the above post, here are some PIREPS from aviationweather.gov, specifically in the origin and destination areas of the proposed flight:

At 1045 MDT today, a Cessna 210 at 13,500' reported moderate to severe turbulence/chop crossing the Collegiate Peaks (Mt. Princeton).

At 1128 MDT today, a Cessna 206 at 14,500 roughly over KLMT/KBJC reported moderate to severe turbulence with downdrafts that exceeded ability to hold altitude.

At 1136 MDT today, regional jet CRJ at 18000 ft reported moderate to severe mountain wave with downdraft/updrafts of +/-2000 fpm.

At 1225 MDT today, a Cessna 172 at 7000' in the KLMT/KBJC area reported moderate to severe turbulence and airspeed excursions in mountain wave activity +/- 20kts.

At 1630 MDT today, a Bonanza at 7200' in the KLMT/KBJC area reported moderate to severe turbulence.

Difficult winds aloft day in the Colorado Rockies.

Good choice to not go today IMHO, good decision making.
 
jb-

Thanks for the info.

I've been following PIREPs today. The winds up here (I am in BV now) are very gusty, again. Monarch pass is still 40+.

I drove up yesterday. Stopped in at the hangar, there was a Cessna 310 at the gas pumps. He took off shortly thereafter ... 2PM, warm, sunny, and surface winds gusting to 25-30.

A couple of guys there said he had just flown in from CA, and the flight over the mountains was "terrible". Apparently he decided to leave because he was afraid he'd get stuck due to the winds.

Personally, I'm not sure taking off mid afternoon in those conditions was the best choice. I sure am glad I drove instead!
 
I am down in Westcliffe (south east of BV) and with the winds we have had the last few days no way I would be flying right now. Sunday is suppose to be a bit calmer but the winds aloft still look a bit high.
 
30kts is a good limit

So I'm not quite half the pilot that some on here are, but I got my training in West TX. That said, winds aloft, who cares, winds on the ground, as long as they aren't gusting >15Kts more than the constant wind speed you should be fine. I'd say go get some decent crosswind training, and do a ton of landing/touch'n'go practice on the non-optimal runway on windy days, and you'll be fine in no time.

A little background, just due to how windy we are generally, we didn't consider it too windy for lessons until the X-Wind component was 20+kts.

I live under the pattern at KFNL and there are days when it looks spectacularly perfect for flying but not a single light airplane is out. This is due to the turbulence associated with the winds at 9,000 and 12,000. These guys telling you 30kts At the ridge level is a good limit know what they are talking about. You did good to ask for local knowledge.

Cm
 
Good article

Below is an example of a severe turbulence encounter (possibly due to flying through the rotor below a mountain wave) that was recently published in KitPlanes. Luckily, nothing that came loose during the event hit the two pilots. But the owner is making changes to more securely tie down items in the cockpit and baggage area.

Thanks Carl - that was a really good article!
 
Long story on flying to BV... sorry for the length

Thomas,

Carey and I have owned a vacation home near BV for 3 years and fly in to KAEJ regularly. I'll reiterate that you have received excellent advice in this thread. And I believe you made the right call, also. I applaud your reaching out to VAF and the local pilot population.

That being said, you asked for real world personal experience from Buena Vista's airport so I'll chime in knowing I open myself up for some likely well deserved criticism. Everything I say below is in reference to my experience flying in and out of BV and nowhere else. We flew out of Buena Vista yesterday after spending a week up there and made it home safely and comfortably. If you talked to Tadd at KAEJ yesterday he may have mentioned that I sent him a pirep after clearing Pueblo.

The route: Our normal route in and out is NW Oklahoma direct Salida direct Buena and the reverse. My strategy usually involves spending minimal time over rough terrain, and 3000 ft over the ridges approached at an angle. It is +- 18 RV minutes from 1v6 (Canon City) to the Arkansas river valley South of Salida, with a couple of private strips along HWY 50 and if you fly to the south a bit there are farm fields available within gliding range. The highway itself is a last choice for me personally as a landing area due to the curviness of the road and usually a lot of traffic.

I considered following HWY 24 through Trout Creek pass, South Park, and Colorado Springs but there is a lot of airspace and the Airforce Academy alert area out that direction and it would have taken me a long way off course.

Planning: Like you I watch the wx for days before planning strategies and deciding go / no-go. Also like you, I made the no-go decision twice the two days prior to yesterday. I'm fairly new to using windy.com but noticed a pattern developing in that if I stayed a bit north of my normal route but still within gliding distance of the highway and the two private airstrips the wind speeds showed to be acceptable to my personal minimums. A real big thing I'd like to emphasize and has been stated in prior posts is land early and take off early. In before 10am and out before 10 am. In this case I was in the air before 9 am. Note: I have slowly worked my comfort level envelope up to the 30 knot winds aloft level that others have mentioned.

At KAEJ: Winds were calm when we arrived, came up from the south while loading baggage, (a King Air took off to the south), then they turned to the north and got gusty before we pulled the airplane out and boarded. There were a few lenticular clouds far down south over the Wet Mountain Valley. At the time I couldn't tell from our vantage point just how far away they were and I was concerned enough about this that I made a conscious decision to do a 180 if I couldn't avoid getting anywhere near them.

The flight: We experienced light turbulence as soon as we took off and during the climb out towards Salida. I've found that which side of the valley you fly matters and the smoothest ride sometimes conflicts with recommended traffic direction. As we kept climbing to 13,500 and turned towards Canon City the turbulence increased. This as expected as I've found that nearing Hayden pass the wind speeds usually seem to increase significantly. I would classify this in my own small airplane turbulence vernacular as somewhere in between light to moderate. It got rough. How rough... I had no issues controlling the aircraft but the control inputs were significantly greater. There was no head / canopy banging or anywhere near to it. I reset my g meter before take off and it indicated a max 1.5 positive g's and .6 negative g's when we got to the home drome.

I would suggest you weigh into your decision your own experience level aircraft specific considerations, and passenger comfort level. We own an RV 7 that has a higher G rating than a 10. I would not have tried this in an RV9. The problem with winds aloft forecasts in that they are just that, forecasts. I have been pleasantly surprised that conditions have been much better than forecast and also a few times found them worse, by a lot. I have been in mountain waves, know how to recognize it and leave myself an out towards lower terrain as others have mentioned in previous posts. There was no mountain wave experienced on this flight but strongly suspect that there was one further south judging from the clouds.

One more thing. Margret Lamb has a paragraph in her book "Flying Colorado's Mountain Weather" regarding the Monarch Pass AWOS. She mentions that it often shows much greater windspeeds than other nearby stations and has found that it doesn't seem to affect the turbulence in the valley as much as you would expect, and I have found my experience to coincide. I certainly check it and pay attention to it but place it secondary to other mountain AWOS sites. Especially Bald Mountain just SW of BV. Now if I was planning to fly over Monarch pass I would certainly treat it differently.

In short I would defer to the other more experienced VAF mountain pilots and CFI's familiar with the area. But in this case my strategy worked quite well but was not without some known risks. Feel free to PM me with questions or comments as well.

Joe
 
Here is a foreflight grab before leaving for the airport showing winds aloft & AWOS info. My big concern was the increase windspeed between 12000 and
15000'.
IMG_0058.jpg
Here is a windy.com screen grab. The plan was to stay north of the purplish area west of canon city.
IMG_0060.jpg
A pick of the mountains flying in a week ago just south of Salida
IMG_4471 (2).jpg
The upside is I had a great tail wind coming over the ridge into Canon City.
IMG_4499.jpg
 

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One thing that bears pointing out - local knowledge is very important no matter which mountains you fly, because not all mountain ranges have the same winds and weather. As has been said in this thread - 30 knots of wind over the Rockies is enough to keep you on the ground, where 30 knots of ridge winds over the northern Sierra is generally fine. But....not 30 knots steady over the southern Sierra!

So the moral is - if you’re from the flatlands, don’t assume that all mountain flying is the same - ask about the specific area you’re interested in (as the OP did here), and never assume that you have it figured out for a place you have never been....

And always leave yourself an out!
 
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