Something weird happened - Mountain Wave in Central Kansas

labbadabba

labbadabba

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labbadabba
Yesterday cruising along the empty skies of Central Kansas at 9,500 catching a 45kt tailwind I was sitting happy as a lark in my C172RG at 170kts over the ground.

I was looking out the window and began to notice my angle changing. It took me a second, I looked back inside to find my airspeed dialing back rapidly and the AP trimming up to maintain 9500. I was under a High Pressure dome so not a cloud in sight. The plane was acting like it was picking up ice (OAT was 25F) but I couldn't see anything.

The only thing that I could really think of was maybe a downdraft. I couldn't quite process it. I was also a touch hypoxic (87%) so I descended to 7,500 and flew the rest of the flight without issue but also with much less of a tailwind.

Can you get a downdraft like that on a clear day at altitude?
 
did your turn on PITOT heat? wondering if that got iced up inside the hole
 
Glad it all worked out for you. Flying by hand was a good decision in those conditions.
 
Walboy said:
If the winds were out of the west, I've heard of mountain waves from the Rockies stretching 100s of miles to the east. Maybe that's what you were experiencing.
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That actually makes a lot of sense. I departed from Hays KS and I pointed out to my PAX the high strato-cirrus clouds showed a striated texture consistent with mountain wave turbulence. There was an AIRMET for turbulence but it was over 30,000ft. I didn't think that at 9,500 it would be an issue but now that I think of it, a downdraft from a mountain wave makes a LOT of sense. I was just south of Manhattan, KS so a LONG way from the Rockies but with the strength of the winds it makes sense.

And yes, I kicked off the AP and hand flew to 7,500.

I learned something yesterday! : )
 
WannFly said:
did your turn on PITOT heat? wondering if that got iced up inside the hole
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I didn't, but the ASI crosscheck against the altimeter, it was not acting like an iced up pitot. Airspeed was dropping, my AOA was increasing, but the altitude was the same.
 
I agree it was probably a Mountain Wave.

Mountain Waves in Kansas. Who woulda thunk it...

-Skip
 
the disturbance causing the wave doesn't have to be a mountain. I notice little wave systems like this pretty often, just above the thermal layer. Thermals in the lower layer pushing up into the inversion can cause some waviness in the inversion that could set off wave above that. In our glider club near Hutchinson we have occasionally had pilots who find wave-like updrafts between thermals & cumulus clouds on days where the wind velocity increases noticeably at the inversion level
 
If there’s lift, there has to be sink somewhere else.
 
tonycondon said:
the disturbance causing the wave doesn't have to be a mountain. I notice little wave systems like this pretty often, just above the thermal layer. Thermals in the lower layer pushing up into the inversion can cause some waviness in the inversion that could set off wave above that. In our glider club near Hutchinson we have occasionally had pilots who find wave-like updrafts between thermals & cumulus clouds on days where the wind velocity increases noticeably at the inversion level
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Yeah, the top of the inversion layer was right at 7,500. Winds there were probably closer to 15kts, whereas the winds at 9,500 were at least 45kts. I'm thinking had I flown thru it another 30 seconds I would have been thru it. But it freaked me out enough and my O2 sats were lowish so I just decided to head lower even tho I was no longer enjoying the winds and I was getting kicked around a fair bit at that altitude (7,500).
 
And the Kansans who were the first politicians named all the downtown streets after themselves. Quite narcissistic really.

They stripped Market Street of that guy’s name when he became the town drunk and would sit under the street sign yelling that he was the guy the street was named after.

Guess they thought it made them look bad. :) They we’re competing with a different group of politicians in Central City for who would become the capital.

Then they had to figure out how to turn the grid and lay the rest of the streets on cardinal headings instead of aligned with the river.

They never learn with that making things named after themselves. The suburb I used to live in named the new jail after the Sheriff. Who was later arrested for meth use and investigated for a murder, and locked up in his own jail.

Presidents courted Horace Tabor during the silver boom. Always here gladhanding and big parties. Stayed at the Brown Palace. Hiked the underground tunnels to the red light district so they would t be seen riding over there.

They were, of course, nowhere to be seen to visit Baby Doe in her old age, guarding the Matchless Mine.

It’s nice to know politicians never change. :)

I’ve held a couple of the ornate beaded playbill covers that Baby Doe used in my hands. Apparently playbill covers for going to the play, were a fashion thing for the rich back then. They’re part of the locked up collection at the Denver Public Library. Quite colorful, most beaded and with lace.

Special access thru taking a Colorado History course. The instructor was also an archive librarian. Pretty neat.

Got to hold the first printed copy of the Rocky Mtn News, too. May it Rest In Peace. Well the plastic cover anyway. It’s printed on butcher paper and quite fragile. Edges are brittle and breaking off. Surprised we weren’t asked to leave it lying flat.
 
Things can get bumpy on the top of an inversion, particularly if there is a big wind speed or direction differential above and below. Also, high pressure days can sport some pretty strong thermals with no corresponding cumulus clouds due to dry air. I was flying yesterday in FL, saw some birds circling ahead of me. Knew the thermal was coming so just flew without adjusting anything, went from 0 on the VSI to +800 fpm, pretty smooth, barely felt the climb and airspeed hardly dropped. Could see the same happening with a broad area of sink.
 
denverpilot said:
...competing with a different group of politicians in Central City for who would become the capital...
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Do you mean Golden? I know Golden and Denver had a big argument over capital city rights ... I hadn't heard Central City did, too.
 
gkainz said:
Do you mean Golden? I know Golden and Denver had a big argument over capital city rights ... I hadn't heard Central City did, too.
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Both I believe. But checking online there were three territorial capitals, Colorado City, Golden City, and Denver.

Not finding the reference to Central City right now which makes me want to go dig thru my books.

I may be mixing up Colorado City, which was near modern day Colorado Springs.

But I do know William Loveland founded Golden and was ticked when Denver was considered for the capital of the State since Golden had once been the territorial one.

He tried to build a railroad spur between Central City and Golden to get the Union Pacific to bypass Denver altogether.

Teller and Berthoud raised $100K back then to finance a line from Denver to Central City and Union Pacific went with them. Later those two paid their own local railroad workers to finish the Kansas Pacific line into Denver.

All sorts of railroad shenanigans continued after that too, of course. But by summer of 1870 Denver had two railroads (UP & KP) and Golden still didn’t have one.

So by statehood in 1876, the infrastructure pretty much made Denver a done deal.

For those not from here, Loveland’s name graces both the pass that was the US-6/I-70 Route over the mountains before the Eisenhower and Johnson Tunnels were built, and also a ski area...

Berthoud Pass is what you cross to get from Denver to Winter Park and it’s essentially part of the areas near Corona Pass that you hear tell of here I’m mountain flying posts... that is a flyable pass and charted as that name on the sectional charts... that folks mention for departing westbound our of Denver in singles, and... apparently now an unfortunate name, just like my dog Rona right now... LOL...

Henry Teller’s name is on various stuff also. Senator. There’s streets and such, but most natives will probably think of the Teller House in Silverton.

https://tellerhouse.com/about-us/

Most of them make Bezos look like a saint. LOL. What a bunch of serious jerks. Haha.

This Knick knack paperweight keeps following me around from the Mayflower Mine in Silverton. The San Juan Historical society sells or used to sell them after tours.

Dirty Subaru bumper for scale. Some might say I only have one ball... but it’s made of steel. :)

Heavy too. Hard to carry around. :) :) :)

673af35fbf986520e5f14fb70130874e.jpg
 
By the way to keep somewhat on topic. Worst mountain wave strength wise (not turbulence wise) I ever flew in was just east of Corona Pass.

Up and down 3000 ft-min at full power and idle. Wheee.

I knew it had to stop before Berthoud Pass or I needed to bail. Wasn’t horribly rough but I stayed out of the lee one the north side. Wouldn’t clear the pass westbound if it turned into a downer. Visualizing it that day it should NOT have turned into a downdraft but I was hair triggered to get the flock out of the pass if it even twitched.

It stopped. Well smooth massive headwind from the other ski area (Eldora) to the pass so no freight elevator down into the rocks.

That was the Denver to Vegas flight to go get the Monkey, outbound leg. :)

I was on flight following from Denver Center. I had to ask for a block. They assured me nobody else was quite as stupid as me that day and I had the whole pass to myself.

In the end I went over it fairly high. Had a plan and flew the plan. Was quite willing to GTFO of there if needed that day. :)
 
labbadabba said:
Yesterday cruising along the empty skies of Central Kansas at 9,500 catching a 45kt tailwind I was sitting happy as a lark in my C172RG at 170kts over the ground.

I was looking out the window and began to notice my angle changing. It took me a second, I looked back inside to find my airspeed dialing back rapidly and the AP trimming up to maintain 9500. I was under a High Pressure dome so not a cloud in sight. The plane was acting like it was picking up ice (OAT was 25F) but I couldn't see anything.

The only thing that I could really think of was maybe a downdraft. I couldn't quite process it. I was also a touch hypoxic (87%) so I descended to 7,500 and flew the rest of the flight without issue but also with much less of a tailwind.

Can you get a downdraft like that on a clear day at altitude?
Click to expand...

What about a simple wind shift/shear at that altitude. If you lost your tailwind, the initial loss in IAS would cause your autopilot to pitch up to maintain altitude until a new equilibrium was established in the new air mass to reestablish cruising IAS. Your ground speed at 9500 would then not be the 170kts you were enjoying.
 
denverpilot said:
By the way to keep somewhat on topic. Worst mountain wave strength wise (not turbulence wise) I ever flew in was just east of Corona Pass.

Up and down 3000 ft-min at full power and idle. Wheee.

I knew it had to stop before Berthoud Pass or I needed to bail. Wasn’t horribly rough but I stayed out of the lee one the north side. Wouldn’t clear the pass westbound if it turned into a downer. Visualizing it that day it should NOT have turned into a downdraft but I was hair triggered to get the flock out of the pass if it even twitched.

It stopped. Well smooth massive headwind from the other ski area (Eldora) to the pass so no freight elevator down into the rocks.

That was the Denver to Vegas flight to go get the Monkey, outbound leg. :)

I was on flight following from Denver Center. I had to ask for a block. They assured me nobody else was quite as stupid as me that day and I had the whole pass to myself.

In the end I went over it fairly high. Had a plan and flew the plan. Was quite willing to GTFO of there if needed that day. :)
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So which pass did you take that day? No flying experience there but I drove the route up Berthoud Pass and then past Winter Park on my way to Steamboat. That Pass is a switchback with part gong almost north/south and I can see how one could be exposed to a variety of down/updrafts depending on wind direction either before or after.
 
MajorTurbulence said:
So which pass did you take that day? No flying experience there but I drove the route up Berthoud Pass and then past Winter Park on my way to Steamboat. That Pass is a switchback with part gong almost north/south and I can see how one could be exposed to a variety of down/updrafts depending on wind direction either before or after.
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Corona also known as Rollins.(kinda. There’s a naming problem up there and nobody really knows why FAA uses the other name, but been that way... forever... :) )

Berthoud is south of it and not really a flyable thing.

You “fly past” Winter Park to get into Rollins.... was just mentioning it for a geographic reference to the area to tie the history to the flying story. :)

The winds up there can be way beyond the capability of a light aircraft on a bad day, and gorgeous on a calm day, for sure.

That day was very “iffy”. No passengers for sure, plan was to bail out if the stuff was too rough or downdrafts were in “the wrong place”.
 
Salty said:
If there’s lift, there has to be sink somewhere else.
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This is exactly what I was thinking. Mountain wave or not, all that air going up is displacing the air that's already there and forcing it back down. If there are gliders out and about and finding their way up to where you are, and higher, know you're likely to encounter some heavy up and down drafts.
 
Years ago I saw a satellite photo on TV that showed striated clouds parallel to the Rockies and stretching for hundreds of miles east of them. I figured it was mountain wave. I wish I had had the means of capturing an image.
 
apr911 said:
This is exactly what I was thinking. Mountain wave or not, all that air going up is displacing the air that's already there and forcing it back down. If there are gliders out and about and finding their way up to where you are, and higher, know you're likely to encounter some heavy up and down drafts.
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My glider instructor beat that into me when I complained about getting nothing but sink everywhere I went. Only he said it the other way. If there's sink, there's got to be lift somewhere else.
 
Salty said:
My glider instructor beat that into me when I complained about getting nothing but sink everywhere I went. Only he said it the other way. If there's sink, there's got to be lift somewhere else.
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One time when I was approaching Tehachapi Pass in a Cessna Cutlass from the southeast, I got into a really strong downdraft. I don't remember whether it was stronger than the climb capability of the airplane, but it had me worried enough so that I took advantage of the above principle by turning away from the ridge until I found an updraft, and I spiraled up in it to 14,500 or 16,500 before crossing the pass. (I had O2 on board.)
 
Palmpilot said:
One time when I was approaching Tehachapi Pass in a Cessna Cutlass from the southeast, I got into a really strong downdraft. I don't remember whether it was stronger than the climb capability of the airplane, but it had me worried enough so that I took advantage of the above principle by turning away from the ridge until I found an updraft, and I spiraled up in it to 14,500 or 16,500 before crossing the pass. (I had O2 on board.)
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I was flying a Cutlass on this flight. 700fpm all the way to 9500. Trued out at 135kts on 9gph. Almost 1,000lbs useful. I don't know why they get such a bad rap.
 
labbadabba said:
700fpm all the way to 9500. Trued out at 135kts on 9gph. Almost 1,000lbs useful. I don't know why they get such a bad rap.
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I think the rap came from before 182 prices went insane. I never *disliked* flying the 172RG as a renter/instructor, but I always felt like the gear would make the operating costs pretty close to a 182. So if it's gonna cost the same to fly around at 135 knots anyway, you might as well have the bigger cabin and better useful load of the 182.
 
labbadabba said:
I was flying a Cutlass on this flight. 700fpm all the way to 9500. Trued out at 135kts on 9gph. Almost 1,000lbs useful. I don't know why they get such a bad rap.
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It's one of my favorite types for cross-countries. There used to be a couple of them for rent at my home field, but no more. :(
 
Salty said:
My glider instructor beat that into me when I complained about getting nothing but sink everywhere I went. Only he said it the other way. If there's sink, there's got to be lift somewhere else.
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Perhaps a glider CFI can jump in here, but I never found this to be true in early evening when the daily convection stuff was falling down due to loss of heating. Way more sink than lift.
 
kayoh190 said:
I think the rap came from before 182 prices went insane. I never *disliked* flying the 172RG as a renter/instructor, but I always felt like the gear would make the operating costs pretty close to a 182. So if it's gonna cost the same to fly around at 135 knots anyway, you might as well have the bigger cabin and better useful load of the 182.
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They use less fuel than a 182, which translates into lower rental prices. They are also a lot easier to push back into a parking space, which is a factor at my age.
 
denverpilot said:
Perhaps a glider CFI can jump in here, but I never found this to be true in early evening when the daily convection stuff was falling down due to loss of heating. Way more sink than lift.
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The air has to go somewhere. If air is falling down in one place, it has to be rising somewhere else, or in the case of a slope in the evening, turn into horizontal wind. Over the flats, it tends to just stop lifting and sinking as the day shuts down. During the day, there are liftlines (and sinklines), where you can go for miles in lift or at least not sink. (so 200 fpm lift in my HG). Someone can be flying the same heading, but a few hundred yards away from you and be in sink the whole time. During a hang gliding competition, you have 60 or so pilots all flying the same area, course and glider model all doing somewhat better or worse relatively in our very dynamic atmosphere. If I'm flying, I can almost guarantee, I'll find the sink.
 
This incident could be related to a known but uncommon phenomenon which was associated with the Iowa Soaring altitude record set 3 May 2014 by my friend and fellow glider pilot, Don Gurnett (yes, the University of Iowa space probe guy).
His altitude was 13495 with altitude gain of 11395 set in a 15m glider. What happened was it was a day with very good thermals going to about 6,000 feet. That day, a strong wind from Canada blew in and when it struck the thermals it acted as if it had struck a mountain and was deflected upward. My point is that if the wind goes up, it also someplace has to go down and someplace someone could have been in significant sink.
 
Hang 4 said:
The air has to go somewhere. If air is falling down in one place, it has to be rising somewhere else, or in the case of a slope in the evening, turn into horizontal wind. Over the flats, it tends to just stop lifting and sinking as the day shuts down. During the day, there are liftlines (and sinklines), where you can go for miles in lift or at least not sink. (so 200 fpm lift in my HG). Someone can be flying the same heading, but a few hundred yards away from you and be in sink the whole time. During a hang gliding competition, you have 60 or so pilots all flying the same area, course and glider model all doing somewhat better or worse relatively in our very dynamic atmosphere. If I'm flying, I can almost guarantee, I'll find the sink.
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Right. And I’m thinking about the cooling down time where it’s all collapsing and becoming mostly horizontal at the surface, along with turbulent “dry” microbursts.

It’s mixing more earlier while parcels are rising and making more vertical turbulence.

Technically there’s also no “hard top” on the atmosphere. The whole thing can expand upward over a spot without inducing any down nearby. Kinda.

But it’s not totally a closed “something up right now something else must be falling right now” thing, AFAIK.
 
I almost took a flying job in Kansas once. I couldn't stay there, I was afraid of the flat ground....
 
labbadabba said:
It's hilly-er than you might think. But it ain't the Rockies...
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There are the Smokey Hills and the Flint Hills, where Knute Rockney and the Norte Dame Football team crashed and died.

Also, going West, there is quite a bit of elevation gain.
 
Talking about updrafts, I guess a tornado is a kind of updraft, and KS has lots of them. The easiest way to find a tornado is to find a trailer park!
 
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