1. Group work by:
William Agyakwah
John Nguyo
Zablon Shilenje
Noah Eledi
Strong Winds; A Case Study in
Nakuru, 13th
March, 2013
Source jamaicansmusicz.com

2. Introduction
 Wind is moving air caused by differences in air pressure
resulting from differential heating from the sun. The greater
the difference in pressure, the faster the air flows (Ahrens et,
2012)
 On a global scale, the temperature difference between the
tropics and the poles causes strong winds
 Winds are commonly classified by their spatial scale, their
speed, direction, e.t.c.

3. Measurement of wind speed and
direction
 Wind vanes
 Radio-sondes
 Beaufort scale
 Radar
 Satellite
 Aircraft
 Pilot ballons / optical theodolite

4. Beaufort
Wind scale speed in km/hr Description
0 Under 1 Calm
1 1 - 5 Light air
2 6 - 11 Light breeze
3 12 - 19 Gentle breeze
4 20 - 28 Moderate breeze
5 29 - 38 Fresh breeze
6 39 - 49 Strong breeze
7 50 - 61 Near gale
8 62 - 74 Gale
9 75 - 88 Strong gale
10 89 - 102 Storm
11 103 - 117 Violent storm
12 Over 118 Hurricane
Forms of strong winds
NB: 30 knots = 55.56kph

5. Impact of strong winds
http://certifieddisaster.com

6. Strong winds are generally experienced in rift valley around
January- March
There exists a channeling effect in the Rift valley which
results in strong air current flow
On a much smaller scale, differential temperature gradients
between land/lake and between mountains/valleys often
create strong breezes.
Wind Characteristics in Kenya

7. Case Study:
Nakuru, 13th
March 2013
Heavy wind swept across Nakuru town on March 13th, 2013 afternoon and left
traders and building owners counting their losses.
Several buildings and cars belonging to staff and individuals in and around the
former provincial headquarters were destroyed as the winds blew away part of
rooftops in several commercial buildings.
The strong winds swept in from the northern side of Nakuru town forcing traders,
business operators and retailers to scamper for their safety as it blew away
anything on its path.
Several individuals were seriously injured in the tragedy.
Nakuru town has been experiencing persistent windy periods during the dry
season.
Residents feared that worse incidents may occur in future and called on relevant
authorities to intervene and establish mechanisms that could forestall such
destruction.
(KTN Television, 2013)

8. Case Study Objective
 The study inquires whether it is
possible for the Kenya Meteorological
Service to forecast strong winds in
Kenya

9. Climatology of Nakuru
 Located at Lat 00
, 16’S and Lon 360
, 06’E
 Elevation 1,901m AMSL
 Nakuru has a warm and
temperate climate
 Average temperature 17.5 o
C
 Population 1,603,325 persons
 Area 7,510 km²
(source; KBS, 2010)

10. Damage caused by Strong Winds in
Nakuru on 13 March, 2013
Play Video (courtesy of KTN Television)
The roofs of classrooms
were blown off in the
afternoon incident that
disrupted learning
activities at the school.
A section of the walls
also collapsed on impact
during the afternoon
incident.

11. Observed METARS at Nakuru
METAR HKNK 1000Z 03O20KT 9/9 SCTO32 29/04 =
METAR HKNK 1100Z 03O10KT 9/9 SCTO32 29/03 =
METAR HKNK 1200Z 06O10KT 9/9 SCTO32 29/05 =
METAR HKNK 1300Z 03O10KT 9/9 FEWO32CB BKNO32
31/05 =
METAR HKNK 1400Z 0103OKT 9/9 FEWO29CB BKN030
29/02 =
METAR HKKK 1500Z 01O10KT 9/9 FEWO28CB BKN030
25/10 =
Note change in wind speed, temperature & CB

12. Dominant wind
direction was North
North Easterlies (NNE)
Recall eyewitness
account in clip, that
strong winds swept in
from the northern side
of Nakuru
Wind roses for Nakuru between 1000 - 1700Z
on 13th
March, 2013
Data source; KMS
No satellite image as we were not able to retrieve any

13. Our View On The Case Study
Question
Is possible for the Kenya Meteorological
Service to forecast strong winds?.
Yes, it is likely to forecast strong winds
but challenging to a forecaster with
limited observational data and other
forecasting tools e.g. high resolution
numerical models

14. Conclusion & Recommendation
 Strong wind are both disastrous and
beneficial
 The strongest gap winds are typically in
the gap exit region
 We need more monitoring instruments
in Nakuru area

15. References Materials
 Ahrens, C. Donald. Meteorology today: an
introduction to weather, climate, and the
environment. Cengage Learning, 2012.
 Kenya National Bureau of Statistics, 2010
 Kenya Television Network broadcasts, 2013
 Kenya Meteorological Service, dataset

16. The End
Thank you