I would like to post a small advice: know the river or lake before you go swimming into it. If you don't ask the locals.
I'm from northern Italy and we have a lot of small rivers and lakes here, from the outside most of them seem pretty innocent but there are drownings every single year.
Most people that drown here are immigrants that don't know how treacherous an alpine river or lake might be, it usually happens in the summer and is always a sad story to hear. A couple of weeks ago two people died in my province: the son went swimming, an undercurrent pulled him under the surface, then his father tried to save him and got pulled under in the same way.
Interestingly, undercurrents aren't as common as people think.
Most currents can't pull you under the water. There are notable exceptions such as obstructions, dams and rapids which can form "keepers", or sudden depth or width changes that can make the water flow extremely fast and turbulent beneath the surface (such as the strid), but those sorts of situations aren't that common.
Most drownings in rivers and lakes where someone was apparently pulled under are actually due to cold water shock. The water beneath the surface of a river can be extremely cold, which can immediately paralyse even the most experienced swimmer.
Worse, sometimes the water can be a lot colder than other times, or colder in the middle than at the sides, meaning the river could be safe sometimes and not other times, and it might seem fine when you first get in, only to find you rapidly fatigue as you move further away from the bank.
That's why I'm posting this advice, they are not common if you count all lakes and all rivers in the world but they are very common in the rivers and lakes near where I live for example.
That's why most drownings around here happen to immigrants: local people know that it is crazy to go swimming in some places, because they know that something bad happened to a lot of swimmers over the years in those points, but if you don't know that history it is easy to make that possibly fatal mistake.
I saw a video of a small stream and I mean small just 2m across a bit more in other places but it can be 10m deep! It looks like you can step in to your knees but really it's very deep.
It's in England it is called Bolton Strid. I'm not in England myself I just read about it.
Do you know if there are public resources one can check to know how to stay safe, or is asking locals the best options? My only gripe with that is that it’s not always possible, one might find oneself by a seemingly nice river/lake with nobody around.
Out of curiosity, what's dangerous about Alpine lakes? I understand that rivers can have currents that can pull and hold people underwater, but I can't think of a risk for lakes other than hypothermia.
I can only answer for the lakes near where I live and that I know, for example Lake Iseo o Lake Como.
They might look all calm and placid, but they are really deep with steep shores that are pretty irregular, think of them as a valley between two mountains filled with water with water coming in from one side and going out from the other (that's exactly what they are actually).
The water flows more rapidly beneath the surface and creates turbulences due to the irregularities of the shores, so now there are two things:
- those turbulences might pull you under very rapidly, many meters below the surface, and that might cause you a shock. If you pass out when that happens, well... you're dead.
- those turbulences and the currents sometimes detach boulders or other chunks of rock, when this happens water needs to fill the void left by the fallen rock and if you are unlucky to be in that water it can pull you down for tens of meters. 10m of water on your head increase the pressure by ~1atm, if you get pulled under by 20/30m in just a second you will pass out for sure and as in the other point... you're dead for sure.
If you go to one of those lakes and want to swim you must stay close to the shore and you must enter the lake where the shore is not steep or else you'll be risking it.
Lake Garda, Lake Idro, Lake Moro and other are very much safe on the other hand. That's why asking a local person is often wise: it just takes a couple of minutes to find someone and ask, after you know you're safe get into the water and enjoy :)
On jumping in, you can get cold water shock, which can cause involuntary gasping and loss of muscle control, leading to immediate drowning. The water doesn't even have to be that cold.
I'm from northern Italy and we have a lot of small rivers and lakes here, from the outside most of them seem pretty innocent but there are drownings every single year.
Most people that drown here are immigrants that don't know how treacherous an alpine river or lake might be, it usually happens in the summer and is always a sad story to hear. A couple of weeks ago two people died in my province: the son went swimming, an undercurrent pulled him under the surface, then his father tried to save him and got pulled under in the same way.
Please be careful!