26
votes
Under what circumstances, if any, can thunder by itself cause damage?
Yes, and it apparently happened (article in German)
The paper reports from an incident in 2017 where a severe thunder blast destroyed windows. It has several images on what that looked like.
Bringing ...
- 1,368
20
votes
Accepted
What is the relationship between altitude gain and temperature decrease when mountaineering?
The answer is that it depends on the moisture held in the air
moist air changes at a rate of 3° Fahrenheit per 1000 ft of vertical / 0.6° Celsius per 100m.
dry air changes at a rate of 5.4&...
- 69.2k
20
votes
Accepted
Why do upside down tree leaves mean rain
This is the old saying, "When leaves show their undersides, be very sure rain betides." From the farmersalmanac.com:
The leaves of deciduous trees, like maples and poplars, do often to
turn ...
- 2,750
19
votes
What is a 'Whitecap' and why should I be concerned about boating in them?
White caps are named for the white caps at the top of waves.
White caps are sign that the wind is picking up and that the weather conditions are getting worse and look like this at low wind levels.
...
- 69.2k
14
votes
Accepted
Why doesn't it snow much at -30 °C?
It's actually kind of the other way around, it's not that being too cold prevents snow from falling, it's that an absence of moisture in the air allows the atmosphere to cool.
Low pressure systems ...
- 53.4k
14
votes
How long after a storm is it safe to go into the forest?
Personally I'd pass through the forest once the wind has died down significantly. I'd go a little more cautiously on a bike, because I wouldn't want to ride round a bend into a fallen tree.
That's ...
- 25.8k
13
votes
What is a 'Whitecap' and why should I be concerned about boating in them?
As well stated in another answer, whitecaps (the white tips of waves) are a visual indicator of local wind speed over the water.
Just wanted to add emphasis that whitecaps, as an indicator of wind, ...
- 3,486
12
votes
Under what circumstances, if any, can thunder by itself cause damage?
I can't address whether it's actually happened but it could:
https://en.wikipedia.org/wiki/Thunder
In close proximity to the source, the sound pressure level of thunder is usually 165–180dB, but can ...
- 2,324
11
votes
Accepted
How do you predict weather with an altimeter while mountaineering and or backpacking?
On a backpacking trip, calibrate the altimeter only at the trailhead and at places, such as a pass or a lake, that are marked on a topo map. In your comment you mention maybe calibrating the ...
- 23.1k
10
votes
How do you assess the weather when getting an alpine start?
It's usually not that hard to detect clouds at night after your eyes have adjusted to the darkness. So assessing weather at night is not much different from doing it when the sun is out.
However, ...
- 21.4k
10
votes
Accepted
How do you assess the weather when getting an alpine start?
I think you have already answered. Check for clear sky or how the overall weather feels like. A barometer could give you a brief indication as well.
Ideally, you have left home with an idea of the ...
- 2,338
10
votes
If you are canoeing on a lake when whitecaps start happening, what is the best direction to get off the lake?
I was always taught that it is best when possible to "three quarter" the waves, whether your intended direction of travel is up or down wind -- either way this avoids most splashing, and the boat will ...
- 795
9
votes
Accepted
What do surf report terms like "fading WNW swell" mean?
Wind directions are always given as the direction the wind is coming from. It would be natural for surf reports to do the same.
This is born out by looking at Surfline surf reports for the West ...
- 1,831
8
votes
What are good indicators of hail approaching?
Hail is a result of the same type of instability that causes thunderstorms. Not all thunderstorms have hail, but most hail is part of a thunderstorm. Therefore, all the same warnings for ...
- 21.4k
8
votes
Does firewood have to be stored inside or is storing it in a lean-to sufficient?
Very simply, the drier the wood, the more efficiently it burns, and the easier it lights.
A lean-to on the downwind side of the house is very common as a long-term wood store (there's generally a ...
- 25.8k
8
votes
What signs can I use to navigate a cave if lost?
When you say "trapped" I presume you mean he cannot find his way out, as opposed to being trapped by rock fall or something blocking his exit such as flooding?
The only weather-related clues could be ...
- 5,970
7
votes
How to get weather information in the backcountry
The National Weather Service offers a REST Web Service to provide forecast data in XML format. You can request forecast data using latitude and longitude, start and end dates, and forecast data ...
- 8,418
7
votes
Accepted
What are good ways of predicting incoming weather from the downwind side of a mountain?
I don't think there is any pat answer to this - weather patterns can vary widely by region and by season. All I can suggest is some commonsense approaches:
Check the weather forecast before your ...
- 11.7k
7
votes
Accepted
Mountain guide leading towards a thunderstorm - does his explanation make sense?
In general the idea (#1) of the guide is not a bad one but it is way simplifying weather forecast. It is not as easy to predict even short-time. Of course it could be a local guide with lots of ...
- 12.1k
7
votes
Mountain guide leading towards a thunderstorm - does his explanation make sense?
The guide's argument seems to be reasonable. However, I would not recommend to simply copy that behaviour but try to go with the more conservative advice you were given.
The guide has one big ...
- 7,502
7
votes
Reacting to tornado warnings while camping with no buildings nearby
Tie your canoe off to a tree or big rock and sink it in a shallow area (chest deep) it will be safe till you need to retrieve it same with equipment that dosent matter if it gets soaked through (pots ...
- 71
7
votes
What type of weather conditions would lead to being above the clouds while mountaineering?
There are various factors to lead you being above the clouds.
Mainly what you want to do is to be on top of a mountain during Thermal inversion.
From wikipedia:
In meteorology, an inversion is a ...
- 2,338
7
votes
How can I tell how much, if any, rain is in an approaching cloud?
Randall Munroe has the single best article on this I have ever seen, over on his What-If site where he discusses what would happen if all the water in a cloud formed one giant raindrop.
I recommend ...
- 24.9k
7
votes
Accepted
Heat index vs feels like temperature
One-liner: Wiki thinks its the same. Although Wiki is not always perfect about information it posts, the justification there make sense to me.
Looked up at Heat Index wikipedia, it says,
The heat ...
- 31.7k
6
votes
Why does the 528 thickness lines only appear on weather maps in the future?
At least in the US forecast models do change. In unsettled air they change faster. Two possiblies come to mind for why this line would "disappear" or move to another day. Both are kind of related.
...
- 224
6
votes
What type of weather conditions would lead to being above the clouds while mountaineering?
Many clouds are below mountain level
Common Cloud Names, Shapes, and Altitudes
The lower are typically cooling of air and not limited to an inversion
Stratocumulus Clouds (“The low, puffy ...
- 7,156
6
votes
Why doesn't it snow much at -30 °C?
Any place that snows has the saying "too cold to snow," and it's generally true. Not that mere cold prevents snow formation, but that the coldest weather is generally clear and cold, with no ...
- 12.1k
6
votes
How can I tell how much, if any, rain is in an approaching cloud?
Isolated clouds are going to be easier to judge than gradually thickening cloud cover, as cloud height is important. I assume you've already established that the cloud is approaching you, though you ...
- 25.8k
Only top scored, non community-wiki answers of a minimum length are eligible