Mountain winds and weather

[Sparkie]

I'm hoping that someone like Little Storm Cloud can answer this one.

I have a story idea that involves some people living in a mountain mining settlement getting caught in a dangerous windstorm. I'm not very smart when it comes to things of this nature, so any reliable, authoratative information on the title subject is welcome and appreciated.

These are my main questions: Is there a time or season when mountain winds are particularly strong? Is it possible to have a windstorm in a mountain range without rain, sleet, or snow? Would the wind be a downdraft blowing down the slope, or otherwise?

Please help!!! I have a good idea (for once,) and I need to know how these sorts of things work.

 

[San Cidolfus]

Well, I'm no meteorologist, but I started paying more attention to weather after a tornado mowed over my apartment, so I can give you basic information.

Strong weather can pop up any time of the year, but seasonal storms depend on where you live. As a Floridian, I know this better than most. But assuming you're not in hurricane country, storm systems happen when hot and cold air fronts collide or when areas of high and low pressure mash together. The boring details don't really matter unless one of your characters is a weatherman. But to keep it general, for mountainous areas, it's natural to go with a wintertime storm. Cold air swoops down from northern climes and brings with it all the nasty weather effects we come to expect: snow, hail, etc.

You asked if wind storms are possible without rain, sleet, or snow, and the answer is absolutely yes. If it's just a cold front swooping in without a lot of humidity to cause precipitation, then you're just going to get frosty coldness and a metric butt-ton of wind.

So far as the direction of the wind, it depends on the orientation of the storm front and how it hits your mountains. Mountain chains tend to run north-south or east-west when we look at a map, but if you actually get into mountains it's a lot more cluttered. So really it comes down to leeward and windward: the lee side of the mountain is the side opposite which the wind is hitting, so it has shelter; the windward is opposite, directly exposed to the wind. So for all intents and purposes in your story, it just matters on which side of the mountain they're standing.

Really, in a strong storm, wherever you are on the mountain you're going to feel it. It's just a matter of whether or not you feel thirty mph wind or eighty mph wind. Trees will dilute that force a fair deal, but also add the hazard of debris falling on your characters. Rocks make for poor cover, unless you find a nice, cozy crevasse.

You can decide where and how powerfully the brunt of the storm hits; you're the writer, after all, and that comes with perks, like godlike powers to control the weather!

 

[Jess A]

Hello,

I unfortunately do not know a lot about mountain weather. I can likely tell you more about thunderstorms, although I am still learning and most of my knowledge comes from direct observation. I will relate what I do know about mountain weather and I will look around for some information.

I think San Cidolfus has actually covered the things which I would have said. I would also be inclined to have a storm occur in winter time, but strong winds can occur any time of year (from my experience living here on the coast - most unfortunate) and can create hazardous conditions any time you, the writer, wants. Winter and spring for example are times to be wary of in the Rocky Mountains of Colorado. Spring is always a variable season (I call it 'see-saw' season).

I would also agree that the dangers to your characters depend on where they are. However, if they are on the side of the mountain opposite to where the wind is hitting (the lee side), then down-slope wind storms can occur. Winds can hit a mountain and then race down the lee side at extreme speeds. This probably refers more to winds travelling down onto plains than within the mountain range itself, but it might happen on a different scale within the mountain range (i.e. with mountainous territory on either side of your characters). I am not sure. Wind speeds can be very strong above the tree line. Are your characters above or below the tree line?

Interesting topics to look up: Chinook winds, valley winds.

This site has a bit of cut and paste info on a message board: Winds; Mountain,Valley,Static,Dynamic

Mountain weather can be very unpredictable, which can be a factor in your story.

I have forwarded your question to some friends of mine who know a lot more than I do. I hope that they can help. I will get back to you with an answer as soon as (and if) I get a reply. Since they are all Western Australians, they might not have a huge amount of knowledge on mountainous weather, but a few of them have meteorological training as far as I know and would still know the basics. Some might do a lot of hiking and skiing over east.

 

[Ravana]

Basically, what they said. Windstorms could take place at any time of year, depending on local weather patterns. Direction, ditto, though in most cases the wind will be coming horizontally—its normal tendency, barring exceptional controlling factors. A high-level cold air mass could turn into a downdraft, though I'm fairly certain this is only likely if it's coming down off an elevated area (a higher plateau, for instance); otherwise, it would already have sunk. Strong updrafts are less likely, as there would be little preventing warm air from rising any time it felt like doing so rather than waiting until it reached the mountains. Precipitation would depend entirely on how much moisture the air is carrying, which in turn depends on what sort of surface terrain it's been passing over, for how long, how distant the nearest large body of water it's passed across is, temperature… all sorts of things. Dry is just as likely as wet, possibly even more so, especially if the air has already crossed other elevations (which are prone to inducing moisture to precipitate out).

Unless the people were near the top of the mountain (unlikely, if they're "mining"—though it is certainly possible if they're trying to work a seam exposed only near the top), there's also the possibility of the wind's force being increased if it's being channeled into a narrower area… and increased a lot if it's been howling along between two ranges of similar height for some time.

See also mistral and tramontane—cold, dry winds; simoon and sirocco—hot and dry (and more associated with desert than mountains); or Santa Ana, dry, either hot or cold.

 

[Jess A]

Someone I know who works for the Australian Bureau of Meteorology got back to me with a few links:

http://www.ess.uci.edu/~yu/class/ess124/Lecture.17.mountain_windstorm.all.pdf

http://www.aos.wisc.edu/uwaosjournal/Volume1/AOS453/FCS_Hruska.pdf

http://www.wrh.noaa.gov/wrh/TA1101.pdf

A Wind-storm in the Forests, Chapter 10, ‘The Mountains of California’ by John Muir (1894) - John Muir Writings

Just a quick google search. Common for Iceland too to get windstorms.

I hope these are helpful. It was most kind of him to get back to me. I have learned a little myself from reading up on this. There are so many things to learn whilst writing a novel. I am always happy to expand my knowledge. Thank you for asking me.

 

[Sparkie]

Great stuff, people. Just what I was looking for. Thanks for the help!

Now to make notes...

 

[SeverinR]

Hurricane force winds in Ohio, believe me winds can happen anywhere.
Winds tend to follow a pattern. We normally get winds from the west, from the north Canada. Hurricane winds came from the south west(via Texas).

Little Storm cloud: thats why I love research forum. No matter what the topic, you get alot of different ideas and learn stuff too.

 

[Caged Maiden]

I live in Albuquerque, and know a thing or two about mountain wind.....
It is calm most mornings, and wind only picks up in the afternoon. It can get 60-80 mph gusts on even a sunny bright day. There is no clouds/ rain/ storm required. Two days ago, it was sunny and bright all day, then in the late afternoon the wind picked up and crap blew all around outside, pelting my house and windows relentlessly until well into the night.

If it is a dry climate, there will be considerable pollen, dust, leaves and other junk in the wind, and let me tell you, it stings and you feel sand-blasted. Also, just as a side note, Albuquerque is 5000 feet above sea level, but the mountain top is 10,000. Both have separate ecosystems because of the drastic climate difference due to elevation. At this elevation, some plants cannot thrive (like hollyhock, can you believe it?) because they are unable to draw water up their stalks, and many insects are missing because of probably similar reasons.

Today it was about 50 degrees and it will be 27 overnight. That gives you an idea of how quickly the temperature drops, and it would be more drastic on the mountain.

Regarding wind.... The wind here always comes from the west, but the most damaging wind storm we've had was about 3 months ago, when the wind came from the east. Everything here is tempered against the normal wind, but when it changed directions, power went down, trees fell over, (along with my fence), and a lot of other damage happened to houses and buildings.

 

[Caged Maiden]

A perfect example of it was last year when Arizona had those major fires. We are like 400 miles away, but every evening, when the wind picked up, Albuquerque was covered in a weird-colored haze and it stunk like smoke everywhere. People with health conditions had real problems because it was hard to breathe for several weeks until the fire was out. That's the power of the wind out here. It's pretty terrible, but not the sort of gales my husband grew up with in England. Mountain wind is different than ocean wind.