Ricochet News

Severe Weather Early Warning issued for areas between Cape Point and Cape Agulhas

Jul 10, 2018
Severe Weather Early Warning issued for areas between Cape Point and Cape Agulhas

The SA Weather Service has warned local residents of adverse weather expected between Thursday and Friday.

"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," said the SA Weather Service in a statement.

"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."

Otto added that 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."

Hazard

Alert Level

Valid From (SAST)

Valid To (SAST)

High Seas

Watch

12/07/18 00h00

13/07/18 00h00

 

High seas with wave heights of 6 to 7m are expected between Cape Point and Cape Agulhas during Thursday late morning spreading to Cape Columbine and Plettenberg Bay during the afternoon and subsiding during Friday.

 

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," it said.

"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."

The weather office said that 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."