How high does the Apalachian mountain chain have to be to block out the cold? (climate, warm)

[antinimby]

I've noticed how the really high mountain ranges like the Rockies and Himalayas seem to block cold air so I've also wondered if the Apalachians can do the same for the East Coast US.

[Baba_Wethu]

It does already block a bit. Problem is that it lies in a north-to-south angle kind of, which means it doesn't really separate southern and northern weather so much as it separates western and eastern weather. However, places closer to it (especially close to the higher parts), are affected. Cumberland, Maryland on the east side/inside the Apalachians for example, has 1.5-3'C higher average highs in every month compared to Morgantown, West Virginia right on the west side, with similar lows.

[FirebirdCamaro1220]

Usually for a mountain range to effectively block a cold airmass, it's peaks have to be 10k ft or higher, cold airmasses usually sink down below 10k ft

[Warszawa]

Originally Posted by Baba_Wethu

It does already block a bit. Problem is that it lies in a north-to-south angle kind of, which means it doesn't really separate southern and northern weather so much as it separates western and eastern weather. However, places closer to it (especially close to the higher parts), are affected. Cumberland, Maryland on the east side/inside the Apalachians for example, has 1.5-3'C higher average highs in every month compared to Morgantown, West Virginia right on the west side, with similar lows.

Thankfully it does make a bit of a difference, areas to the east of the Appalachians are about 2-3c warmer in December and January than those to the west, of course it could be just coastal influence

[grega94]

Originally Posted by FirebirdCamaro1220

Usually for a mountain range to effectively block a cold airmass, it's peaks have to be 10k ft or higher, cold airmasses usually sink down below 10k ft

The cascades are good at blocking cold air, and they are not nearly that tall. WA only has 4 peaks taller than 10K one of which is a satellite peak on mt. Rainier. OR has another 4 peaks taller than 10k. Instead I would say a good height would be when the mountains reach the timberline. Here in WA that is between 5 and 6k which the majority of the cascade mountains are of this height.

[FirebirdCamaro1220]

Originally Posted by grega94

The cascades are good at blocking cold air, and they are not nearly that tall. WA only has 4 peaks taller than 10K one of which is a satellite peak on mt. Rainier. OR has another 4 peaks taller than 10k. Instead I would say a good height would be when the mountains reach the timberline. Here in WA that is between 5 and 6k which the majority of the cascade mountains are of this height.

The Rockies are the real "cold blocker" for the west, and the spine of the Rockies averages 10k ft+

[Warszawa]

The Andes block the air too, enough that the two sides of the Andes have completely different climates

[CraigCreek]

See also the "thermal belt" area of western North Carolina, where altitude, topography, and weather patterns combine for a limited area of milder temperatures and a longer growing season. Tryon, NC is located in one such belt.

[grega94]

Originally Posted by FirebirdCamaro1220

The Rockies are the real "cold blocker" for the west, and the spine of the Rockies averages 10k ft+

Well for one the Rockies sit atop a ~5k ft tall plateau so the actual mountains are only about 5k and secondly then explain this:

Baring, WA: https://en.wikipedia.org/wiki/Baring...ington#Climate

Baring is on the western edge of the cascades at 774 ft elevation, it receives 107.55" of rain, has a Jan avg of 36.1F and a record low of 1F.

Wenatchee, WA: https://en.wikipedia.org/wiki/Wenatc...gton#Geography

Wenatchee is on the eastern edge of the cascades at 780 ft elevation, it receives 9.12" of rain, has a Jan avg of 29.2F and a record low of -19F.

The pass connecting the two places is Stevens pass at an elevation of 4,056 ft and the peaks in this area are around ~7k.

Or these two.

Greenwater, WA: https://en.wikipedia.org/wiki/Greenw...ington#Climate

Greenwater is on the western side at an elevation of 1,699 ft, receives 57.03" of rain, has a Jan avg of 31.3F and a record low of -8F.

Ellensburg, WA: https://en.wikipedia.org/wiki/Ellens...ington#Climate

Ellensburg is on the eastern side at an elevation of 1,542 ft, receives 9.1" of rain, has a Jan avg of 26.2F and a record low of -31F.

The pass separating the two is Snoqualmie Pass at an elevation of 3,022 ft and the peaks in the area are about ~ 5k.

[Saritra]

Cold, probably not too much of an effect.
They definitely have a noticeable effect on weather, though. There is a noticeable rain-shadow to the east and a high-precipitation area to the west, and the mountains often break up or at least weaken thunderstorms passing through.