At what wind speed is hiking considered unsafe

Question

I have enough experience with mountain hiking, but in the area where I live (the Alps), the wind rarelly gets extremelly strong, so I have no idea about judging when it is actually unsafe to hike because of high wind speeds.

This winter I was in Tenerife, where I have attempted to climb Mount Teide. Due to public transport limitations I have decided to divide my climb into two days, and spend the night in the hut. On the first day, the wind was already very strong, but being sheltered by the side of the mountain, I had no problems reaching the hut. The people coming back from the peak, however, were all talking about how much trouble they had on the more exposed parts of the mountain.

I was hoping the conditions would get better on the following day. But in the morning the wind picked up even more. It was constantly between 90 and 100 km/h. Since there also was a thick fog, and I would have seen absolutelly nothing from the top of the mountain, I have decided to give up, and head down instead.

Ever since I have been wondering: had I decided to push on to the top, would it have been dangerous? What wind speed is too high for mountain hiking?

Edit as an answer to comments:

There was no snow or ice, so avalanche or slipping dangers were not an issue. The path itself was not technically challenging on its own (in good weather conditions tourists do the last bit after taking a gondola). The climb was super exposed though: no vegetation or shelter at that altitude, and Tenerife being an island, the winds come directly from the ocean. As I haven't been to the top, I am not able to tell how risky a potential fall would have been, but let's assume that like in most places in the mountains, there were at least some spots where the path was passing close to cliffs.

Actually, I do not want to make the question too tailored to this specific situation, because I prefer the answer to be usable in future situations I (or somebody else) will have in the mountains. All I want to know, if there is a specific estimate, how strong should a wind be, to be able to blow an average adult person off a cliff. I do understand that in specific situations where balancing is important (ridge crossing, scrambling or other technical climbing, etc) the safe wind speeds are surelly much lower.

Answer 1

By the Beaufort scale if would be over level 8,

• Level 7: 50-61 km/h, 32–38 mph: Inconvenience felt when walking against the wind.
• Level 8: 62-74 km/h, 39–46 mph: Twigs break off trees; generally impedes progress

Source

Or from the National Weather service levels,

A Wind Advisory means that sustained winds of 30 mph for one hour and/or frequent gusts of at least 45 mph are occurring or expected within the next 36 hours. These winds will make it difficult to drive high profile vehicles. Small, unsecured objects may be blown around by these winds.

A High Wind Watch means that sustained winds of 40 mph for one hour and/or frequent gusts of at least 58 mph are expected within the next 12 to 48 hours. Check to make sure all loose objects outside are secured. Plan to postpone any unnecessary driving during this time since these winds will make driving difficult, especially for high profile vehicles. These winds may damage trees, power lines and small structures.

A High Wind Warning means that sustained winds of 40 mph for one hour and/or frequent gusts of at least 58 mph are occurring or expected within the next 36 hours. Ensure that all objects outside are secured. Refrain from any unnecessary driving during this time since these winds will make driving very difficult, especially for high profile vehicles. Winds this strong may damage trees, power lines and small structures.

Source

I have a great deal of personal experience with the wind in Wyoming, and you can go hiking in 50-60 mph winds, its just not pleasant. Whether or not it will knock you down and be unsafe depends on the person. You would also have to consider the risks of what would happen if the wind did knock you over. On an exposed ridge that would be a bigger deal than a flat hillside.

Answer 2

There is already a good answer to this but I'll add a slightly different perspective, especially since you noted in your question you want more general answers.

For working in the forest - as in forestry, logging, land surveying - the safety guidance about wind I was taught as a professional is as follows.

Sustained winds over 15 miles per hour present a hazard and you should proceed with an abundance of caution; where normally you would look up and down often for hazards and wear a hard hat, now you need to be extra diligent in those precautions and consider changing your course of work to avoid areas with weak limbs or trees likely to fall. Examples of that kind of area include coniferous forests with dead branches hanging on the tree (as with white pines or red spruces), or areas with lots of standing dead trees yet to fall.

Sustained winds over 30 miles per hour are generally not safe to work in, as it is likely there will be falling debris which could be very dangerous. Course of work should change to avoid forested areas that could drop limbs and trees in high winds.

---

I see these as rules of thumb and on the extra-cautious end of the safety spectrum. For recreational hiking, you may be inclined to take more risks. For folks working in forests every day, extra caution needs to be practiced because it's easy to get casual and overexpose yourself to life-threatening risks.

It's important not to underestimate the dangers here: 15 mile per hour wind can seem fairly gentle and branches falling may not seem like a big deal, but even with a hard hat on if a falling branch hits you in the head it can easily knock you out and/or greatly hinder your ability to safely get out of the woods and back in contact with civilization, or worst case outright kill you. I've never come across specific numbers on this but I'd point out that a fairly small diameter branch (say, 4 inches) can be very heavy, and if one were to land on your head with no other person or telecommunication contact within hours walk, you could be in a life threatening situation. Is that likely to happen? No, it would be pretty unlucky, but it does happen. Again, for hiking these might be acceptable fringe risks, but for an already-dangerous day job it's worth carrying extra caution.