The weather will be crucial to your success on
Everest. You will find yourself frustrated by itís power to make you or
break you. When you are ready, the wind might be yelling above you, when
you decide to wait - the sun might shine from a clear blue sky.
will lay at night in camp 2 and listen to the roar of a distant train
-the Jet wind. You will turn your face countless times towards the
ridges of the mountains, trying to make some sense and predictions of
the dancing white tails of snow. To go or to stay - the decision will be
like gambling red or black in Las Vegas. Your odds of the correct move
just as poor.
Did you see Everest - the movie?
We were there in 1996.
We wrote this guide, our friends wrote books.
Get the full picture straight from the horseís mouth:
Going too soon will mean wearing yourself down, having to climb back
all the way to BC and your chances lost until you regain strength for a
new attempt. Waiting too long means happy Summiteers greeting you on
their way down while the weather is turning worse on you.
Expeditions sometimes share weather reports, subscribed to from
various meteorologists. Daily weather reports are costly and therefore
more frequent close to the time of the summit push. ExplorersWeb now
provides daily customized weather reports free of charge. Expeditions
download them on satellite phones and distribute them to those without
Whilst weather reports can be quite accurate, there is a local
weather system on the mountain that they canít foresee. Therefore, a day
with reported mild wind conditions could very well turn into a blowing
frenzy, or reported strong wind nowhere to be seen.
The best way to read weather reports has always been to look for
extended changes in the weather pattern. 4-5 following days of high or
low figures is often a good chance of good or bad weather. Use the
information to rest or to climb.
When not to climb
Jet stream is the main concern on Everest weather. This westerly wind
will have a large impact on your choice for a summit day.
We have experienced C2 in total calm, while
the jet wind roared at the summit with a force of more than 100 miles an
hour (50 m/s). In these conditions, the sound is that of a jet-engine
and gusts drop down at 50 mph (25 m/s).
Sometimes, the jet wind will rise and give a short period of calm and
a summit attempt might be possible. A summit bid in these conditions is
however hazardous. You will encounter people making the summit in
perfect calm one day, while the next day others hardly make it above C4.
At times the jet wind is gone, but the weather is still unstable. At
the time of the 1996 accidents there were just those unstable weather
patterns. Dark blizzard clouds emerged from the valley. One of the
strongest teams on the mountain (the IMAX) actually returned from C4
that day, only to meet a large group of people going up in the high
winds and deteriorating weather. Well, the rest is history.
Don't climb if the weather forecast is jumping back and forth and/or
there is snow and strange cloud formations. Use common sense. Don't
climb if it is snowing. Sherpas go back to sleep if there is a heavy
snowfall, and so should you.
When to climb
we primarily look for is a prolonged period (4-5 days) of stable weather
with the jet far away. This is called "the window".
During our four Everest expeditions the window has come every year at
about the same time, around the 23rd of May and has lasted for about a
week. To find a window, it is valuable to look for the Monsoon starting
to move north in the Bay of Bengal. The weather report will tell you
when that occurs. This powerful weather system will pressure the jet
wind to the north and create a period of perfect weather.
Don't wait too long though. As the Monsoon hits the Khumbu valley
with heavy snowfalls, you should already be back in Kathmandu.
A problem with waiting for the window could be other climbers. Most
expeditions schedule their attempt for the 10th of May, and by the 23rd
at least half of the expeditions will have returned home. Most
commercial expeditions have an end date around the 20th. When you plan
for your expedition - make sure you have the resources to stay until the
permit ends (1st of June).
there is a period of weak winds and good weather in the beginning of May.
You should be ready for summit attempt already from the 1st of May to
take advantage of this.
If you don't summit on this first, early attempt, there will be
plenty of time to go down the valley for a week's rest, and then head
back up for a new attempt in the end of the month.
The wind force forecast should definitely not exceed 40 mph (20 m/s)
when going for the summit. You could maybe make it in 50, but then you
are extremely exposed for the wind-chill and exhaustion. In these
conditions you will hardly make the summit without frostbites - or worse.
Look for less than 20 mph (10m/s). Even if that doubles, you will
have a good chance of making it.