Spring is fully here in Colorado

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Spring is fully here in Colorado

Postby Benzie » Thu May 11, 2017 7:03 am

Spring is fully here in Colorado, the moment we have all been waiting for. So watch out and fly safe.
In the last month and a half the weather has turned from late winter to full on spring/summer flying. I have felt this shift and want to remind everyone to make good conservative decisions out there.

This is an interesting time of year for flying. The shift in the weather patterns and conditions for flying have been ramping up drastically each week. In March, on a good day, around here strong P3 pilots seem to be able to fly mid day without much issue. The thermals may have some punch, but generally they are mellow. Now, a month later, things are completely different. I have been getting out a lot and I can attest that conditions have changed dramatically. The thermals have been strong and punchy, and at times really rowdy; the sink as well. Spring can have the most rowdy days of the year. I want pilots in Colorado to recognize that.
Now, on most of our local sites, we have air hungry pilots experiencing this shift. Lots of pilots are able to fly mid day in the winter and early spring. Most pilots don't fly mid day in the summer and for good reason. And, spring is the most rowdy time of it all. So, if you weren't flying mid day conditions last fall, it is that time of year to start reeling it in a little bit. For a lot of pilots this means limiting flying to the mornings and evenings and progressing from there.

If one wants to start xc flying in this state I recommend working on your skill set progressively through the summer so that you are ready to make some nice xc in the fall. September and October consistently have the best mid day flying of the year. I encourage pilots that are working their way into xc to shoot for this time of year to make it happen.
I have been getting some nice flights lately and sharing that stoke here on the web. And I hope this gets pilots excited about flying and expanding their skill sets. But I don't want to encourage people to jump into some air that is more gnarly than they are prepared for. And I don't want to give a FALSE impression of what it is like out there. Flying here mid day is rowdy turbulent and often windy. I have a ton of flying and forecasting experience. I go out on only the right days and make it a priority not to push it. Yet I still feel that most big days push me to the absolute limit of my flying skills. And when the conditions push too hard, I go land in a safe place. The camera only comes out for the smoothest part of the flight if at all.
I would love to hear what other pilots are experiencing in other parts of the state.
I wish everyone safe and enjoyable flights.

Pete FlyGuy
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Re: Spring is fully here in Colorado

Postby laminar » Thu May 11, 2017 9:35 am

My message is avoid thunderstorm / cumulonimbus

In my experience the the biggest cause of hang gliding fatalities is related to thunderstorms. I've seen the results first hand, made the same mistakes and lived to tell about it and sometimes just got surprised or fooled by conditions.

My opinion is that over the years we learn this lesson and then gradually, as pilots relate the strong smooth lift they found under dark clouds we get complacent and even think that our speedy wing can get us out of harms way.

This time of year the Pacific Maritime flow from the North West rides over the moisture laden air coming up from the Gulf of Mexico and with the strong sun and latent energy from the moisture there is nothing to hold back the over development. The cumulonimbus take on a life of their own as they draw in vast amounts of air and convert the latent energy of the condensing moisture into cloud suck. We don't want to be caught fighting to get down or in the air wondering what to do when the gust fronts are pushing through below us.

Springtime gives us good conditions and the days are long. Consider flying earlier or during the magical evening glass offs.


BTW - I don't know what the statistics are for paragliding but the larger slower wings would be more susceptible to getting sucked up or landing backwards.

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Re: Spring is fully here in Colorado

Postby garyvail » Thu May 11, 2017 10:34 am

thanks everyone for posting,

i was always taught when the clouds start growing taller then they are wide its a sign of potentially dangerous conditions


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Re: Spring is fully here in Colorado

Postby jjhildebrand1 » Mon May 15, 2017 9:53 am

Yeah... Let's dive into the topic of latent heat release, in the context of clouds!

To build on Larry's one point, latent heat... Some wonder why the lift gets stronger near cloudbase (assuming the cloud is growing and not dying). The reason is, like Larry noted, is due to the mechanism of latent heat release of condensation. Latent is just a meteo term for hidden. As air (dry, not moist/saturated) rises (thermal, wave, fart, etc), it cools adiabatically at the dry rate of 9.8 c/km (5.4 f/1000') until the air condenses, and thus saturates, at the point where the air temperature meets the dewpoint temperature. Simply stated, the meetup altitude is where cloudbase exists (you can find this altitude on a Skew T plot). Once the air condenses, it releases its latent ("hidden") heat, which adds additional heat to the already rising thermal column, in an environment that is cold (at altitude and under the shade of a cloud). This latent heat that is released rises in this steeply lapsed environment causing even stronger, and more widespread lift. Not sure exactly about this part, but my theory is that well below cloudbase you have the lift rate of the thermal but when you get near cloudbase, where the air is starting to saturate (wispies are a good sign of this), the latent heat is released causing additional lift, at around the rate associated with the moist adiabatic lapse rate (which is variable due cloud microphysics). So basically, why lift can get so strong and thus Hoover-like just below a cloud, is that you have the lift associated with the newly released latent heat ADDED to the lift of the thermal. It's a summation game. Hypothetically, let's say you're having fun in a thermal that is rising at 800 fpm, and as you get closer to cloudbase, you encounter additional "new" lift of 1000 fpm due to latent heat release. You can see how this addition of the lift from latent heat can suck you up. Spiraling down in 800 fpm is no prob, but spiraling down in 1800 fpm is much more challenging. Further, the lift due to heat release is more widespread than the isolated thermal column width. So, even if you escape the band of 1800 fpm lift (thermal lift rate summed with the lift rate associated with the latent heat release), then you still have to deal with the larger-diameter under-cloud latent heat release lift (1000 fpm). This might be just enough to suck you in as you're trying to make a run for the edge.

Rich? Correct me here where I'm off.
, ) jake

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Re: Spring is fully here in Colorado

Postby bjherring » Tue May 16, 2017 3:45 pm

I remember MR saying at just the right times: "If you're going up, it's not because of your superior skill". Lots of times, he'd say that right as the latent heat machine was turning on. I used to get into lockjaw thermal mode when I was learning and sometimes would forget to watch the way the clouds were changing so always appreciated his direct remarks.

I guess I'm getting old b/c of this penchant for telling stories, but here's a memory from Lookout. It's a kinda extreme example of the latent heat machine turning on but it still applies in parallel to typical days when any OD is forecasted.

This was a fairly good spring day where 75+% of launches were getting up for us and XC was pretty easy up and down the front range. I think it was around 3:30 or 4 when things changed. I had been to Morrison and back a few times and was planning to top land but was taking my time enjoying the feeling of being low near launch. The lift had ended around 10 or 11k that day so far. Anyway, over 5-10 minutes, things got noticeably more boaty all over and exploring north of launch it got better and better. Light lift all over really but I decided to circle in a little stronger part that I think was 3-500 fpm all the way around. The characteristic that's unique to the latent engine is there wasn't really any sink. The edges of the lift I was in were bordered gently by a little less lift... no real sink. The higher I circled, the more the vario started sounding like a fire engine.... but it was a smooth transition from 600fpm to 7 to 8 and up. It's never been this easy, holy shit I was thinking. Partially elated, and partially checking myself to see if I'm doing something stupid. Later, the track log confirmed gaining over 5280ft in 5 minutes. It was the smoothest 1000-1300 fpm I'd ever been in and it went all the way up. I forced myself to start moving to the edge of the cloud from several thousand feet below it just to make sure I had insurance that I'd make it out of this monster. Seemed crazy to move to the edges from so far below the cloud but since the rate of climb was only getting stronger, I figured might as well be safe. Flying straight, my climb rate continued to rise as I approached the edge. It wasn't a cu-nimb yet. I remember the cloud had a concave bottom and I just made it past the lower edge of the cloud somewhere between 13 and 14k. I was stoked but now realized I didn't want to hang around to see what came next so flew straight in my Sport2 all the way back past Morrison to my house. Landed and that same cloud followed me and dropped cats and dogs on me when I was breaking down.

I remember lots of days where the conditions went from hard to stay up, to boaty and easy to soar, and then sometimes to nuclear. If there's a forecast for OD and/or if any clouds are popping up higher than they are wide, I finally have built a thermaling governor in my head saying "the day is pretty much done, make a plan to get down somewhere". "And don't by any means keep trying to get to cloudbase".

Zapata flying had a semi pure reference/calibration on latent heat's power it seemed like. At 8:15am when the sun isn't doing squat, it was possible to soar under the cloud streets. There was about 400ft under the clouds in that scenario that would give access to the latent heat/suck. If we got below that, it needed to be a little later in the day for the ground convection to get you back up to the cloud suck. Totally unscientific opinion/mileage here.

Anyway, old man 2 cents, signing off.
Jack Handy

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