Turbulence over the Sierras

[RobertE]

Two days ago I had to fly from the Bay Area to Las Vegas. The direct route would take me over Yosemite and Bishop. The highest peaks are 11K and span a region of about 80 miles given my path. There was an airmet in the area for moderate turbulence below 12K, so I chickened out and went via Palmdale, which involved just a brief crossing of 8K peaks, adding 30 minutes of flight time.

Had I flown direct I'd have done it at 14 or 15K.

What sort of flight should I have expected? Would most have gone direct?

Thanks.

[rahill]

I would have taken the route you took, especially in winter when the options are slim over that part of the Sierras. The other option, if you want a slightly more direct route than the Palmdale one, is to go via China Lake and navigate through the restricted areas.

[rainman]

Robert, you picked a route you were comfortable with....isn't that what risk management boils down to?

[Joe Zuffoletto]

This time of year turbulence over the Sierras is caused mostly by the prevailing westerly/northwesterly winds off the Pacific tumbling over the terrain. My experience is that if you get high enough you can escape it and enjoy a smooth ride. 15K probably would have been the ticket and that's what I would have tried, although with a J model (no turbo) I think you made the right choice because if was still bumpy at 15K you probably couldn't have climbed any more.

[DaV8or]

I personally wouldn't fly over 80 miles of unsurvivable terrain no matter what the winds are doing. I would take the route you took no matter what.

[M016576]

Two days ago I had to fly from the Bay Area to Las Vegas. The direct route would take me over Yosemite and Bishop. The highest peaks are 11K and span a region of about 80 miles given my path. There was an airmet in the area for moderate turbulence below 12K, so I chickened out and went via Palmdale, which involved just a brief crossing of 8K peaks, adding 30 minutes of flight time.

Had I flown direct I'd have done it at 14 or 15K.

What sort of flight should I have expected? Would most have gone direct?

Thanks.

In Feb of 2011, I was flying a FA-18E on a simulated strike mission from the carrier up to Fallon to drop a 2000lb JDAM on B-20. I was part of a 4 ship of hornets, and we were being drug by a KC-135 tanker, which was fitted with a 6 foot hose and basket to allow our jets (probe and drogue equipped only) to tank off the big wing jet. I was "in the basket" just north of Mammoth when we hit some moderate turbulence... At FL230. The nose of the hornet kicked up, and the refueling fairing split the hose on the tanker, showering my jet in JP-8.

Turbulence is kind of like icing- it exists where you find it. Your mooney would probably be fine at 12500-14000 through the area you describe- I've flown a J through there at those altitudes, but I think you made the conservative, safe and smart decision.

[bonal]

We flew that route last summer from k1o2 and are going to fly it next week we will pick up a friend in Merced on the way. Looking at the chart it seems a smart way to go. Also from what I'm told you can't count on clearance through china lake I like the route it keeps you over good terrain the whole time.

[N201MKTurbo]

I encountered the worst tutbelance of my flying career over the sierras. 2000 foot uncontrolled vertical excursions. Keeping the plane right side up and the airspeed on the meter was about all I could do. My son was lying on the back seat with his feet on the ceiling to stay in place.

You did the right thing.

[M016576]

We flew that route last summer from k1o2 and are going to fly it next week we will pick up a friend in Merced on the way. Looking at the chart it seems a smart way to go. Also from what I'm told you can't count on clearance through china lake I like the route it keeps you over good terrain the whole time.

I flew out of China Lake for 3 years. On the weekends, as a civilian, you can normally overfly 2505 with Joshua's clearance, above 7K. Talk to Joshua for flight following in 2508, but you should not be denied access to 2508 ever. The corridor up the Owens valley over 395 is very popular for GA traffic: keep your eyes out!

[MB65E]

My Buddy left South Lake Tahoe in his Bravo one morning headed down to LA. Nothing forecasted, VSI pegged, at idle, Boards out. He took a 4500 ft uncontrolled elevator ride from 16k up to 20k. Luckily he never found the sink!

Not to be messed with. From what I can see it's really unpredictable in some parts of the Sierras

-Matt

[OR75]

I flew from the Bay Area to Vegas several times . I used both routes both ways (Yosemite, Mammoth, Bishop route and the Kern Valley/China Lake route)

The Yosemite route seems more appealing for three reasons: it looks shorter and the for China Lake route, you are at the mercy of ATC to cross the restricted airspace R2505.

My experience for both routes:

Bishop route:

- indeed more scenic ( the CA central valley is boring)

- usually more bumpy especially as you cross some ridges past bishop

- you can cross between Friant VOR and Mammoth as low as 10-11000 but there is no escape route. I have had as high as 55kts headwinds in that segment. Very smooth but i was not reassured. the crossing felt like it was taking for ever.

- shorter route , especially if you are going to North Las Vegas

- radar coverage is iffy.

- not many airports on that route. pretty much the desert.

China Lake route:

- boring CA central valley, more scenic between Kern Valley and Las Vegas

- you can cross R2505 if you stay above 10000, but you may be denied crossing. I was told once that I was the last to cross as military activity was starting. If you are denied crossing you have to go through the Trona Pass. GPS is really needed for that and it makes the route slightly longer.

- airports are everywhere ( not many between Kern Valley and Vegas but it is flat mostly)

-ATC coverage is good but you will loose contact before vegas and the last few miles will be very busy between picking up AtIS and talking to ATC ( all in a few minutes)

- steep descent into Vegas

- ATC in Vegas is very helpful (especially if you know where the space needle is if you are landing at McCarran)

-usually smoother ride ( except between Kern Valley and Vegas where it can be a bit bumpy)

overall, I count more on the Central Valley route . But there will be times when the I will still fly the Owens valley. It will depend on weather conditions ( turbulence, winds aloft, Pireps), my mood and what my destination airport is ( central valley if flying to McCarran or Henderson), Owens Valley if going to VGT)

[bonal]

We fly into boulder city rent the car from the FBO and its 15 to 20 min to Vegas easy pleasey japanesey and from what I've read Owens valley can be quite the hair ball.

[ToddDPT]

I fly out of Visalia (as OR75 put it, "the boring CA Central Valley" I just hope he remembers us when he takes a bite of his apple LOL) and I prefer the Trona corridor.  I'm in a J too so I prefer to avoid the higher terrain and add that additional time onto my flight to get into Vegas.  Those Sierras don't give you a lot of outs.  I usually fly the Trona gap and once clear of the Restricted (many times they clear you right through it) I head direct towards Indian Springs/Creech AFB on the backside of the Spring Mountains NW of KVGT.  This is nice because you have a nice decent path into KVGT and with the usual winds you're given downwind for 30.  You don't have to deal with any of the airspace.  You won't have to worry about a rapid descent for your passengers as well.  Is it a little longer...yes, but who cares, it is still faster than flying a 172!  The radio contact is hit and miss between Trona and Indian Springs, but I usually pick back up ATC once I'm near Indian Springs.  In fact, we are going to Vegas this Thursday, but for the fun of it, I'm thinking of going IFR so I will have to go through Palmdale.

[M016576]

I lived in Lemoore for a couple years, and flew my mooney out of Hanford: lots of agriculture. Fantastic produce.

For those of you that live on the coast and are curious where your $200 dollar steaks at the 5 star steakhouses and basically any fresh produce from San Fran on south comes from: it's the Central Valley.

If you want that $200.00 steak- fly your mooney to Harris Ranch and have their porterhouse for $40.00... The steak you'll be eating was saying "moo" to you on your landing. Not only that, but you'll get to log some flight time to get it. Just be careful- you may exceed max gross weight on the flight out of there!

[kerry]

I've fly vegas to the bay area quite a bit.  I use Trona pass just west of R-2505.  Joshua app usually lets me through restricted airspace.  I gone direct before and if something happen there's not many options.  It seems like going direct saves 15+ minutes.  I'd say saving 15 minutes adds lots of risk.

[M016576]

I've fly vegas to the bay area quite a bit. I use Trona pass just west of R-2505. Joshua app usually lets me through restricted airspace. I gone direct before and if something happen there's not many options. It seems like going direct saves 15+ minutes. I'd say saving 15 minutes adds lots of risk.

The "trona gap" is on the east side of 2505. It exists between 2505 and 2524, over the town of.... You guessed it... Trona.

Don't have a chart or GPS on you? Follow the highway- it runs right through the gap- give yourself about half a wing to the south for buffer. Trona may look "industrious" due to the mine, but if you ever drive through there, you'll find out it's pretty remote. You'll also see that while the ground appears flat from above, the terrain is pretty harsh: lots of big rocks / bushes that look like nothing from the air over in the panamint valley. Death Valley, too. Aptly named.

[DaV8or]

I lived in Lemoore for a couple years, and flew my mooney out of Hanford: lots of agriculture. Fantastic produce.

For those of you that live on the coast and are curious where your $200 dollar steaks at the 5 star steakhouses and basically any fresh produce from San Fran on south comes from: it's the Central Valley.

If you want that $200.00 steak- fly your mooney to Harris Ranch and have their porterhouse for $40.00... The steak you'll be eating was saying "moo" to you on your landing. Not only that, but you'll get to log some flight time to get it. Just be careful- you may exceed max gross weight on the flight out of there!

 

Be aware that the approach to Harris Ranch can be confirmed by the Odor Marker. The steaks are good. They now have gas there too!

[OR75]

I lived in Lemoore for a couple years, and flew my mooney out of Hanford: lots of agriculture. Fantastic produce.

For those of you that live on the coast and are curious where your $200 dollar steaks at the 5 star steakhouses and basically any fresh produce from San Fran on south comes from: it's the Central Valley.

If you want that $200.00 steak- fly your mooney to Harris Ranch and have their porterhouse for $40.00... The steak you'll be eating was saying "moo" to you on your landing. Not only that, but you'll get to log some flight time to get it. Just be careful- you may exceed max gross weight on the flight out of there!

i won't disagree with you there.

if the central valley is boring to fly over, plenty of good eateries usually with walking distance from the airport.

Too many to list in here. Harris Ranch is one of them

[FlyDave]

I was a glider pilot before I flew power. As a glider pilot you learn what winds do around mountains (ridge lift and wave) and where to look for lift in the mountains. Glider pilots are looking for unstable air - power pilots are looking for stable air.

As a glider pilot out of the Palmdale area, I used to fly up the Sierra - and most of the time cross over the Owens Valley to the Inyo's and Whites and up into Nevada and points north.

The turbulence we encounter over the Sierra are either mountain wave (typically most severe turbulence AND the smoothest air you'll ever climb and descend in), ridge or thermal lift. Read up on these types of weather to get a good idea of how to predict Wave and ridge. To get an easy to understand forecast of thermal lift check out Dr Jack's blipmaps at http://www.drjack.info/BLIP/ .

It really helps to go fly these weather phenomenon to truly understand how/where wave develops. Years ago in my Cherokee 140 with 2 glider pilot buddies aboard we got to 13,200' in wave in the Owens Valley. If I wasn't a glider pilot I would have been getting bounced around in the rotor wondering if we were going to survive - instead we got to 13,200' and had lunch in Bishop and went home.

As usual, the safest thing to do is avoid these areas when forecast - which is what you did. But learning more about them can only help in the future.

 

Dave

[TTaylor]

If you are not familiar with flying mountain wave and what to look for it was a good idea to go around.  Friday was a strong wave day on the Sierras.  Here is an article with great pictures from Friday.  If you don't know which side of a lenticular cloud is going up and down, what a rotor cloud looks like and what the winds will be doing around a foehn gap it is best to stay away from the lee side of the mountains on a strong wind say.  I would encourage you to read about mountain wave and how to use it to increase the speed of your plane.  Nothing like cruising in the lift along the lee side of ridges and gaining 50 knots of free energy. 

 

 

 

http://soaringcafe.com/2014/03/cross-country-wave-101-with-gordo/

[cliffy]

My first instructor was an old DC-3 driver and found himself in a wave over the Sierras with gear and flaps down, power off and going up at 2000 fpm passing 14,000' in the DC-3!

 

Many years ago I flew a corporate trip to the Trona Airport (can't tell you why we went there or I'd have to kill ya ) and sat on the ramp for an hour watching the Air Force dog fight overhead.  Great air show.

 

Your pick of  route was the correct choice that day. Don't second guess yourself!

[mooneyflyer]

Respect for the Sierra Nevada winds is a damn good idea.  But having said that, it is a shame that pilots shy away from flying over mountains under the right conditions for their airplane and their own skill.  It is one of the most rewarding flights you can make, others being over water to an island, the Grand Canyon, and the like.

 

A rule of thumb, espoused by Sparky Imeson, was/is "If the winds aloft at the peaks are greater than 20 kts, then consider taking a different route.  That works... but it is also true that you can hit mountain weather at any time in any conditions.  BAck up your decision with Airmets/Sigmets and PIREPS, of course.

 

Avoiding lenticulars/rotors in VFR is not much different than avoiding Thunderstorms in VFR.  It can be done easily in VFR.

 

Easiest "last resort" is to perform a 180 back to known conditions.

 

Anyway... the mountains can be an awesome ride... learn how to do it... then ease yourself into it... It's wonderful.

[RobertE]

. If I wasn't a glider pilot I would have been getting bounced around in the rotor wondering if we were going to survive - instead we got to 13,200' and had lunch in Bishop and went home.

I'm curious. How do you fly differently by virtue of your glider experience? How is it you might have encountered the rotor without that training?

[FlyDave]

Robert,

 

In glider training we are taught to look for sources of lift. This includes thermals, ridge lift and mountain wave. Wherever there is rising air (any of these sources of lift), there is descending air.

In general, mountain wave is generated when wind, increasing in velocity with altitude, hits an embankment and is deflected up. Mountain wave is sinusoidal that has down-wind harmonics (repeating "waves" that typically decrease in amplitude and wind strength). Under each crest is where rotor is formed - usually marked by a lenticular cloud. As long as you stay in the ultra-smooth rising air up-wind of the rotor you'll have a nice ride. Fall down-wind into the rotor and you can hit severe turbulence that is a rapidly ascending (upwind of rotor) or descending (downwind of rotor) air mass - now you've got an "E-Ticket Ride". When you fly wave in a glider (or power plane for that matter) you have to feel your way around. Hit some rough air and move upwind and back into the smooth air. But you have to know what the wind is doing (local geography, winds aloft forecast, airspeed indicator, experience) in order to do that. There's more to it than this but generally, that's where you'll find the rotor.

We used to fly though rotor on tow tethered to the tow plane looking for wave. You'll go through a whole box of "Depends" the first time you try that!

 

Dave

[WardHolbrook]

I was a glider pilot before I flew power. As a glider pilot you learn what winds do around mountains (ridge lift and wave) and where to look for lift in the mountains. Glider pilots are looking for unstable air - power pilots are looking for stable air.

As a glider pilot out of the Palmdale area, I used to fly up the Sierra - and most of the time cross over the Owens Valley to the Inyo's and Whites and up into Nevada and points north.

The turbulence we encounter over the Sierra are either mountain wave (typically most severe turbulence AND the smoothest air you'll ever climb and descend in), ridge or thermal lift. Read up on these types of weather to get a good idea of how to predict Wave and ridge. To get an easy to understand forecast of thermal lift check out Dr Jack's blipmaps at http://www.drjack.info/BLIP/ .

It really helps to go fly these weather phenomenon to truly understand how/where wave develops. Years ago in my Cherokee 140 with 2 glider pilot buddies aboard we got to 13,200' in wave in the Owens Valley. If I wasn't a glider pilot I would have been getting bounced around in the rotor wondering if we were going to survive - instead we got to 13,200' and had lunch in Bishop and went home.

As usual, the safest thing to do is avoid these areas when forecast - which is what you did. But learning more about them can only help in the future.

 

Dave

Best post on this thread.