Question about Road Signs

[gramdragon]

My granddaughter recently asked a question that no one in the family could answer. I am hoping that someone here might be able to shed some light on the reason why altitude signs are posted along highways over mountains. Is there a requirement to post the altitude for some reason?

Thank you for any information.

-gramdragon

[Midwest Michael]

Welcome to the RTA Forum!

I don't know of any "requirement" to post it, I really think it is just a case of information that people may find interesting and useful.

[gramdragon]

That was my thought as well. I could not come up with any other reason other than informational. Thank you for responding, and for the welcome.

[Foy]

Hello gramdragon,

Particularly in the West, regular travelers become attuned to how local elevation affects weather. Forecasters often refer to the "snow-rain line" in terms of the elevation at which rain becomes snow as elevation increases. For regular users of, for example, I-80 between Park City and Salt Lake City, UT, a snow-rain line at 4,500' means all of the 10 miles from eastern SLC to Parley's Summit (a pass at 7,016') will be getting snow, and further means the pass itself is 2,500' above the gradational snow-rain boundary. By contrast, a forecast snow-rain line at 6,500' means it's likely Parley's will be an easy ascent that day. Having the elevations posted at key points such as cities and passes is a constant reminder of where the traveler is, weather-wise, enabling better use of the forecasts.

Foy

[DonnaR57]

Altitude used to have a big effect on how certain engines would handle, too. We always found it helpful, when driving our old diesel pick-up, to know how high we were.

But the deal with elevation and weather IS important, as I proved on Sunday Mar. 18th when I drove through the mountains east of San Diego ... snowy!!!!


Donna