How do you calculate the turnaround and start times when summitting mountains?

Question

In mountaineering, the turnaround time is the point in time at which the party will turn around and head down the mountain regardless of how close to the summit. This is typically done to make certain that everyone is down before afternoon storms roll in and put the party at risk.

If I am preparing to climb a mountain, how do I determine what the turnaround times and from that what the start time should be?

Answer 1

Turnaround time will be driven by the time you want to be back to your origin/campsite. You will also need an idea how long the walk itself is going to take. That's quite important and more precise the better. You don't want underestimate and get caught in a night walk in serious mountaineering. Trust me. I've been there.

There are various factors you need to consider to get to this time.

• Daylight. (In my part of the world, sunsets around 22.30 on the longest day and around 16.30 on the shortest day roughly.)
• Weather. (if you know weather is supposed to turn at some point, you need to allow time to get back safely.)
• Season of the year. (It might be a walk in the park during summer but late in the day during winter becomes a bit tricky when snow starts to melt and is prone to avalanches.)

Start time also relies on similar factors.

• Daylight. (In my part of the world, sunrises around 5.30am on the longest day and around 7.30am on the shortest day roughly. You might want during the winter to have an "alpine start" at 3/4am and start the walk in the dark to make most of the day.)
• Weather. (if you know weather is supposed to turn at some point, you might want to start earlier to maybe later.)
• Season of the year. (Pretty much the same as the turnover time.)

Answer 2

The first thing to know is what is the latest you want to be on the summit and aim to be off before then. Then you calculate the estimated time it will take to summit and return. The start time is the the lastest time minus half of the trip time.

So if thunderstorms are know to hit the mountain starting at noon, and to be conservative you want to be off by 11:00 am, and the whole trip is estimated to take 14 hours, then you want to be on the trail at 4:00 am.

11 - (14/2) = 4

If getting down at 6:00 pm would mean that you get back in the dark, then it would be better to get an even earlier start.

If a thunderstorm starts moving in earlier, then you should turn around anyways.

Usually, going up and down take pretty similar amounts of time, but there are few things that make the descent faster, like

• The ability to glissade the slope you ascended
• Rappeling the route

and there are a few things that descent take longer, like

• Getting more and more tired as the day goes on.
• Loosing the sense of urgency that comes with the trying to beat the thunderstorms and so taking your time.