Kilimanjaro was wet through the second half of December, "crazy wet" as characterized by Timba at Ahsante Tours. Telemetry from the Northern Ice Field provides the evidence, with high humidity and snowfall totaling 33.8 cm between 16 December and 3 January. The days of greatest accumulation were the 27th (4.9 cm), 30th (5.2 cm) and 2 January (5.5 cm). Although 5 cm is a moderate hourly rate in some mountain regions, less than 4% of all days with snowfall on Kilimanjaro are of this magnitude. Although such events do not add much mass, they are disproportionally important in terms of raising albedo and thus decreasing net radiation receipt.
Snowfall on the glaciers is often rainfall lower on the mountain,
and often much heavier than summit snowfall might suggest.
Kilimanjaro precipitation is frequently associated with convection,
particularly at this
time of year, and at 12:30 PM on Wednesday (2 January), lightning
struck a group that was approaching Lava Tower. The group leader Ian
McKeever was killed and several other were burned.
McKeever's FaceBook post the day before from Shira 2 camp mentioned
"torrential rain all day", and the group's guide Said Makacha
indicated that there was heavy rain during the hike to Lava Tower.
We have learned that 2 porters have also tragically died in recent
days. At the moment it is unclear whether lightning, hypothermia, or
another cause was responsible; condolences to the families of all 3
Lightning is not common on Kilimanjaro itself (e.g., zoom
in with this Google Earth overlay showing lightning frequency), and deaths are quite rare - especially considering the
number of people camped high on the mountain most nights . An article in the Tanzanian
"Daily News Online Edition" recalls the previous incident in 1999,
which occurred just a couple months before we began working on the
mountain. The article quotes a National Park source suggesting the
terrible idea that climbers take cover in caves (above 4,000 m)
during rain, evidently not aware that the 1999 death occurred at
Shira Caves, a short distance from where the death occurred this
While strikes may be infrequent, lightning is often visible at night from
high on Kilimanjaro, and thunder has been heard while camped at the
summit for fieldwork on the past two trips.
Can we learn anything from summit weather on 2 January that may help
explain the tragic death(s)? Maybe. Wind direction on the Northern
Ice Field blew steadily from the South beginning about midnight, at
a bit lower speed than normal for the day. Southerly flow is
relatively uncommon at our measurement site; wind is more typically
from the East, which helps suppress convection above the mountain's
western slopes (up which many climbers ascend). It is possible that
light winds from the south, in
conjunction with regional instability, aided the development of
convection which led to the lightning strike.
On 4 January humidity decreased dramatically, the wind veered back
to the East, and solar radiation measurements indicate generally