I-70 Across Continental Divide

[spr]

Has anyone flown further south from Pueblo, along US50 across Monarch pass then Gunnison, Montrose, Grand Junction? Monarch pass is 11,300.

[photoSteveZ]

I’m late to this party, but I have a lot of mountain experience in this part of the world, having flown gliders and underpowered single engine aircraft over the high Rockies since the early ‘70s. Crossing the Divide at Rollins Pass and following the Colorado River drainage west towards Grand Junction is your best option to avoid the higher terrain just to the south. The lower terrain at Rollins Pass is actually several miles wide, with a sizable valley immediately to the west of it. If the winds are benign crossing Rollins Pass at 13,000’ is perfectly comfortable, and you can remain over lower terrain from there. You’ll be looking at a forest of high peaks off to the south: that’s the terrain you’d be flying over if you followed I-70.

[photoSteveZ]

Has anyone flown further south from Pueblo, along US50 across Monarch pass then Gunnison, Montrose, Grand Junction? Monarch pass is 11,300.

Yes, many times: it’s a beautiful part of the state. It all depends on the weather, particularly the winds aloft and, of course, the cloud conditions.

[Boatguy]

Has anyone flown further south from Pueblo, along US50 across Monarch pass then Gunnison, Montrose, Grand Junction? Monarch pass is 11,300.

Yes, many times: it’s a beautiful part of the state. It all depends on the weather, particularly the winds aloft and, of course, the cloud conditions.

Steve,

Excluding active weather systems, is there any normal daily cycle in the winds?

More than one mountain flying guide has suggested not crossing in more than 25kts of wind perpendicular to the mountains. Do you have a personal minimum (maximum) for wind conditions in a single versus twin?

[photoSteveZ]

25 knots is a useful rule of thumb, but there are so many variables it’s hard to generalize. This winter I made several crossings in higher winds, but there was no mountain wave activity and little or no turbulence. Every day is different, and the mountains can spring on you any number of unpleasant surprises. I’ve seen updrafts and downdrafts in excess of 1500 fpm in convective conditions, and even higher vertical speeds on wave days.

Try to complete mountain flights before 10am in the warmer months, April-October, because after that thermal convection increases turbulence and vertical motion. Always have a bail out plan if the crossing goes pear shaped. Cross ridges at an angle, so your bailout turn back to lower terrain is shorter and easier. Start your crossing at a comfortable altitude for ground clearance and watch the terrain on the far side of the ridge as you run in: if you’re seeing more and more of the lower terrain just beyond the ridge top, you’re going to clear the ridge; if you see less and less of it, turn away and try again. Many’s the time I’ve made two or three attempts before succeeding. Many’s the time I’ve abandoned the attempt and said to myself, “Tomorrow’s another day.”

If there’s a ridge line leading into the crossing and roughly perpendicular to the crossing, position yourself over that as you run in, biased toward the upwind side if there’s a crosswind on it. Your bailout turn would then be away from the lead in ridge and into the crosswind, reducing your ground speed and distance covered during the turn.

[TimS]

I took a short online mountain orientation course a long time ago. Basically, I think the course was to scare people into playing it super safe.
I followed a lot of the advice when I flew across the country in an NA SR22. Fly early if you want someone to find you, fly very early or very late if you want to avoid thermal effects.

Minimize or preferably set your max altitude based on the available climb rate. e.g. I recall the recommendation as being do not plan on climbing higher than your plane's ability to climb at 500 FPM. If you want to fly higher than that, take mountain flying courses, and learn how to fly in the margins of performance.

Tim