I do a bit of canoeing, here and there. One thing I’ve noticed, is that the wind generally blows upstream, confounding my downstream progress.
It’s possible that I only notice when it blows upstream, and not downstream…but I’m pretty sure I’ve kept good track of the wind direction so that on the rarer occasions it blows downstream, I definitely take notice and rejoice.
Also, it is not the wind in my face because I’m moving in a particular direction; there IS a wind. I know this because I check the grass, weeds and leaves on the bank and see them fluttering upstream.
It seems to not matter if the river is going north, south, east or west.
So why does the wind generally blow upstream on a creek or river?
If you are doing most of your paddling in the afternoon on rivers in or near mountains, you may be experiencing anabatic wind:
If the river you are on is in an area that feeds the anabatic flow, the wind would flow upstream, because that is the direction toward the higher altitude.
As a river guide (sport salmon fishing) in Alaska, I can say that the wind there usually blows upstream because of the onshore (sea) breeze. Similar to what Fear Itself said, the land heats more than the ocean, and thus the wind blows from the ocean to the land.
Since the river is colder than the land, a cold core of air forms along the surface of the river which is denser than the surrounding air. This air tends to run along the riverbed, following the twists and turns as it flows upriver, even if it is not moving directly away from the ocean. This effect can extend for hundreds of miles inland.
Well that’s fine, but I’m almost always on flatland; 2000 miles from an ocean. I’m a couple of hundred miles from the great lakes, but the rivers I’m on don’t flow into the lakes.
And it happens morning or afternoon.
Maybe I should also ask the question, has anyone else noticed this?
I think its pretty easy to establish the air just above the water is cooler than surrounding land, but I would expect that cooler air to descend down the river to a lower elevation.
I guess I just am not completely following those explanations; and am open for further explanation, or new ideas.
Well, one common geological system with streams and rivers is a mountain range with a wind blowing over it. As the wind blows up the one side, the air cools and water condenses out as rain, which drains down the mountains in the streams and rivers. The opposite is happening on the other side, with a now-dry wind blowing down the mountains. If you did your canoeing on that side, you’d have a wind at your back - ah, but that side isn’t where the streams and rivers are.
At least I have heard of this system, though not in the context of canoeing - could this be what’s going on?
Even without mountains, I believe Fear Itself could be on the right track. The intensity of the diurnal wind cycle is related to elevation differences, but even in flatlands it would be present on sunny days.
If the phenomenon is seen even on cloudy days, we may need a different explanation.
Do they tend to flow in the same general direction?
Since I bicycle a lot, I hate wind! Unfortunately, I live in an area where somehow, some way, the wind manages to blow in every direction at once. I’m not joking. One of my regular routes is a 10-mile loop that follows the Columbia River upstream in one direction, crosses the river, and then follows it downstream. And the wind … Howls. In. My. Face. Both. Directions. Grrrrr.
Phase42, I know what you mean. I used to live in Hood River and cycled up and down that valley (which is perpendicular, more or less, to the Columbia) and there was always a headwind no matter which way I was riding. Don’t know how the wind managed to do that.
I’ve noticed it on rivers that flow many directions. Most rivers around here flow generally southward, but not all do and those that do loop many directions.
The anabatic wind idea may be valid, but the elevation difference between the headwaters and where I paddle may be a couple of hundred feet, a hundred or two hundred miles away. I would expect that effect to be much more subtle and imperceptable.
On the Maumee River, which flows from SW to NE to Lake Erie, the general wind direction is out of the south to west, so most often you would be paddling with, not against, the wind.
I seriously doubt there is any substantial evidence of regular winds blowing upriver for all areas; localized conditions might dictate such winds in some cases (e.g.: near a lake in the afternoon in the summer).
Well, I do some kayaking and we have discussed this at times. I think I definitely notice the wind more if it is in my face and impeding travel. However, we paddle upstream (we are masochistic) and note it in our face there as well. When the wind is at my back I tend to not notice it.
If you (or anyone else) are ever in western PA and feel like a paddle, lemme know. Yesterday we went down the Kiskiminetas river, about a 15 mile trip, and had a marvelous time.
Well, I paddled on Crooked Creek last yesterday afternoon/evening with my son and we both tried to stay aware of the wind. We paddled up the backwaters of the lake for 2 or 3 miles. What we found was that when the wind/breeze was at our backs it was barely noticeable. If we were not paying close attention, we would have thought there was zero wind. When the wind was in our face, it was very noticeable. Crooked Creek was a good place to do this experiment because, well, it is crooked!
this is a sideways and up hill wind. It is caused by the sun shining on one side of the valley. This caoses an anabatic wind on the sunny side = you may see para gliders riding the anabatic currents up there. The cool air off the other side floors down across the river and rises up to fill up the space where the air was before on the sunny side - this is the wind you speak of.
If you get up early then you may get a tail wind especially on a cloudy night with low cloud and no wind. The warm air under the cloud cools off and sinks down (a down draft), following the river valley down stream and displacing the warm air. It gathers motion and can build up to be a terrible barber at the river mouth on the coast, This kind of wind is called a Katabatic: from the Greek word katabatikos meaning “going downhill”, this is a wind that blows down a topographic incline such as a hill, mountain, or glacier. Such winds, particularly when they occur over a wide area, are sometimes called fall winds. Californians refer to their great katabatic wind as the Mono wind.
A Foehn is hard to catch but is better than the early morning katabatic (which is freezing cold and can cause ice to build up on whatever it touches e.g. a beard ( hence the name Barber)) because it is WARM air going down stream A foehn is any warm, dry wind that blows down the leeward side of a mountain range; particularly the hot, dry winds that move down from snow-clad mountains to roar through Alpine valleys, typically in autumn and late winter.
I can’t understand this one actually. An example may be the “Sundowner”: warm downslope winds that periodically occur along a short segment of the Southern California coast in the vicinity of Santa Barbara. The name refers to their typical onset (on the populated coastal plain) in the late afternoon or early evening, though they can occur at any time of the day. In extreme cases, wind speeds can be of gale force or higher, and temperatures over the coastal plain and even at the coast itself can rise significantly above 37.8 degrees C (100 degrees F).
Can somebody explain how this works - notmally hot air rises but PV = nRT so why is the hot air going down? The link below may be of use
Incidentally, many words starting with CAT or KAT are Greek in origin w.g Catabolism - the breakdown of tissue protein to feed the energy requirements of the organism ( as opposed
get a strip (maybe 6") of lightweight plastic (like mylar balloon material) and suspend from a horizontal support. watch for a minute or two from a stationary position. do a couple times in a couple locations each trip.
In a small enough gorge the wind always seems to be doing downstream, I would assume that the water entrains the air especially if there are a lot of waterfalls on the stream. I’m talking about the gorges that are small enough to be entirely in the shade.
The picture on wiki explains it a little bit. (For fun compare the English and German page versions )
The warm temperature comes from the fact that on the windward side the air cools only with 0.6°C/100m when it rises because of the energy that the condensing water releases, and on the dry lee side warms with 1°C/100m when it is descending. This warms the atmosphere there in general and doesn’t lead to thermals which come from local temperature differences.
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