Category: Severe Weather Alert

Severe Weather Alert

Hazard Alert Level Valid From (SAST) Valid To (SAST)
Heavy rain Watch 27/11/18 06h00 28/11/18 06h00
Heavy rain is expected in places over the Overberg District and the coastal areas of the Garden Route District today (Tuesday) into tomorrow morning (Wednesday).

Description: Strong damaging winds
Strong damaging winds often occur along coastal regions, but also often occur during thunderstorm activity. These winds are sudden and can cause much damage.

Precautions:  Strong damaging winds
Stay indoors where possible away from the windows that open towards the severe winds. Be aware of the following: – sudden cross winds if traveling especially between buildings, fallen trees or power lines and flying debris.
Small boats must stay away from the open sea and seek the shelter of a harbour, river estuary or protected bay.
Parked aircraft should be pointed into the direction of the wind and secured Listen to the radio or TV for warnings and obey the instructions from disaster management officers.

Description: Flooding / Heavy Rain

Flooding occurs when water overflows its normal channels such as streams and storm water drains. It can occur with prolonged period of rain, with continuous heavy falls or in the form of flash floods which are usually associated with severe thunderstorms. Heavy rain may also result in river flooding causing damage downstream to areas that may receive no rainfall at all during the flooding event.

Precautions: Flooding / Heavy Rain

If possible stay indoors and off the roads, avoid crossing rivers and swollen streams where water is above your ankles. If trapped in flooding in a vehicle, abandon it and climb to higher ground. In buildings, move valuables to a safe place above the expected flood level. Switch off electricity at the supply point to the building. In rural areas protect/relocate animals to a safe place on higher ground. Abandon your home immediately if evacuation is recommended, before access is cut off by flood water. NEVER drive on a road covered by water. You do not know how deep it is or if the road has been washed away. If the vehicle stalls, leave it immediately and seek higher ground. Be especially cautious at night when it’s harder to recognize flood dangers. Listen to the radio or TV for warnings and obey the instructions from disaster management officers.

Duty Forecaster (Cape Town Regional Office – 04h00-20h30)
Tel: +27 21 935 5777
Duty Forecaster (National Forecasting Center – 20h30-04h00)
Tel: +27 12 367 6041
Fax: +27 21 934 3296
E-mail: factfc@weathersa.co.za

Severe Weather Alerts issued by the Cape Town Weather Office

Hazard: Damaging Winds

Alert Level: Warning

Valid from (SAST): 29/10/18, 01h00 – Valid to (SAST): 30/10/18, 11h00

WARNING: Gale force W/SW winds of 65-75km/h is expected along the coast between Hermanus and Plettenberg Bay tonight (Monday), into tomorrow (Tuesday) morning.

ADVISORY: Strong interior winds (50-65km/h) are expected over the Matzikama Municipality, Breede River Valley, Central and Little Karoo today (Monday), into early tomorrow (Tuesday) morning.

Description: Strong damaging winds
Strong damaging winds often occur along coastal regions, but also often occur during thunderstorm activity. These winds are sudden and can cause much damage.

Precautions:  Strong damaging winds
Stay indoors where possible away from the windows that open towards the severe winds. Be aware of the following: – sudden cross winds if traveling especially between buildings, fallen trees or power lines and flying debris.
Small boats must stay away from the open sea and seek the shelter of a harbour, river estuary or protected bay.
Parked aircraft should be pointed into the direction of the wind and secured.  Listen to the radio or TV for warnings and obey the instructions from the Disaster Management Officers.

Description: Storm surges / High Seas

Generally heavy seas or damaging waves are a result of strong winds blowing over a large area called a fetch combined with low pressure systems. Long period swells are often very dangerous to tankers as they may literally snap them in half. Dangerous waves or surges may also be caused by storm surges and tsunami’s resulting in widespread coastal damage and loss of life.

In oceanography, a sea state is the general condition of the free surface on a large body of water—with respect to wind waves and swell—at a certain location and moment. A sea state is characterized by statistics, including the wave height, period, and power spectrum. The sea state varies with time, as the wind conditions or swell conditions change.

Precautions: Storm surges / High Seas

Ships should “idle” into the swell and wind so that the bow of the ship always faces the oncoming swell. If in a small sailing vessel reduce the sail area and steer into the oncoming swell. If along the shore-line stay well back from the highest high water mark as Secure all hatches, doors, windows and ports. Secure all loose items in the interior.

Pump the bilge’s dry and keep pumping them dry at regular intervals. Stow away all loose gear and lash down any large items that cannot be stowed. Break out your life preservers and inform your crew that everyone will be putting them on well in advance of their necessity.

Break out emergency gear like flares and first aid kit, sea anchor, safety harnesses, etc.  Check your position and update your course as plotted on your chart. Prepare alternative routes to more protected areas. If you think you will be in for relatively long haul prepare some hot soup, coffee or stew freak waves may run up beyond the normal high water mark.

If the sea recedes exposing rock and sea bed normally not exposed immediately seek higher ground at least 50m above your current position. Do not try swimming or fishing or other marine recreation during these events. Only extremely experienced surfers will temp their fate under these conditions.

Listen to the radio or TV for warnings and obey the instructions from Disaster Management Officers.

Severe Weather Alert (7-8 September 2018)

SEVERE WEATHER ALERT (ORANGE)
Level 5 Warning for RAIN for 7-8 September 2018.
 
The main areas to be affected will be:
  • Mossel Bay (LM)
  • George (LM)
  • Knysna (LM); and
  • Bitou (LM)
Please note that the YELLOW Level 3 Warning for RAIN issued yesterday remains in place for Hessequa Municipality for 7-8 September.
 
The Garden Route Disaster Management Centre in collaboration with the South African Weather Service will be monitoring the progress of this storm, please activate your local severe weather contingency arrangements and keep the Garden Route Disaster Management Centre updated of any severe weather-related incidents.
 
For emergencies contact 044 805 5071