Severe weather warnings Some definitions Natural Hazard Weather

Severe weather warnings

Some definitions Natural Hazard: Weather or flood-related situation with potential to inflict loss or damage to the community or environment. While hazard may induce a crisis, they do not necessarily lead to disasters. Natural Disaster: A catastrophic event caused by a natural hazard that severely disrupts the fabric of a community and usually requires intervention of government to return the community to “normality”.

Some definitions In some instances, natural disasters can not be prevented from occurring, however their overall impact can be significantly reduced through Disaster Mitigation. Disaster mitigation: Process of managing the “risks” associated with potential natural disasters so that loss may be minimized and even eliminated. - Appropriate Response actions Disaster risk: The likelihood of harmful consequences arising from the interaction of natural hazards and the community.

Some definitions Risk = Hazard Probability x Vulnerability Nature of Hazard: Understand hazards of the past, monitoring of present, and predicting the future. Vulnerability: The extent of a communities susceptibility or resilience to loss or damage from a natural hazard. Reducing disaster vulnerability requires increasing knowledge about the likelihood, consequences, imminence and presence of natural hazards, and empowering individuals, communities and public authorities with that knowledge to lower the risk before severe weather events, and respond immediately during and afterwards.

Early warning Empower individuals and communities to respond appropriately to a threat in order to reduce the risk of death, injury, property loss and damage. Provide early warning of weather, water and climate hazards, for operational decisions Support risk and impact assessments to determine who is at risk and why To improve forecasts and analyses to help reduce or remove risks

Temperature: Very Cold conditions Maximum Temperature below 10 degrees Celsius Minimum Temperature below -10 degrees Celsius

Very Cold conditions: Meteorology Temperature: Very Cold conditions Cold air moving from the far south Maximum Temperature below 10 degrees Celsius Minimum Temperature below -10 degrees Celsius L EUMETSAT MSG: Air-mass image 26 August 2008 07 h 00 Z L L

Very Cold conditions: Highconditions Risk areas Temperature: Very Cold Maximum Sutherland Temperature below 10 degrees Celsius Minimum Temperature below -10 degrees Celsius • Mountains • High lying areas EUMETSAT MSG: Air-mass image 26 August 2008 07 h 00 Z

Snow

Wind Chill conditions Temperature: Very Cold conditions • The colder. Maximum effect that are felt on the skin as a result of cooling effect of the wind. Temperature below 10 degrees Celsius • Felt on the skin and eventually the whole body. Minimum Temperature below -10 degrees Celsius EUMETSAT MSG: Air-mass image 26 August 2008 07 h 00 Z

Temperature: Wind chill Sensible temperature less than or equal to -15 degrees Celsius Effects are worse under wet conditions

Very Cold conditions: At Risk People Senior citizenssettlements Homeless people People in informal Mountaineers, climbers and hikers Increase The sickelectricity usage Pets Added risk of FIRES

Temperature: Very High Maximum Temperature 40 degrees Celsius and above

Temperature: Very uncomfortable Discomfort Index of 38 degrees Celsius and above High temperatures and High humidity

Temperature: Effects Maximum Temperature 40 degrees Celsius and above Sunburn Danger Diminishing Water Resources Hikers Sports Traffic jams

Temperature: Heat-wave Three consecutive days when the Maximum temperature is expected to be at least 5 degrees higher than the average High Maximums of the hottest month.

Temperature and Wind: Veld Fires Weather conditions that could lead to runaway fires. Depends on Temperature, wind conditions, humidity, condition of fuel etc. Climate change: Longer fire season for west coast and adjacent interior, central Western Cape

Wind: Gale force winds or higher Winds speeds greater than 35 kt or 65 km/h Major effect on fishing Industry particularly off west coast Risk of falling, fallen and blowing debris

Wind: Widespread sandstorms Normally in windy, low vegetative areas: West coast north of Lamberts Bay May become more prevalent in climate change scenarios Scouring effect Very low visibility Dangerous road conditions Dangerous flying conditions

Temperature: Black frost The freezing of plant sap that results in black appearance Of the plants. Farmers and Gardeners

Wind: Tornadoes Manenberg, 1999 Harrismith

Springbok!! In 2008

Severe Thunderstorms Traffic jams: Obvious danger to Aviation Lightning: Electricity spikes and power outages

Hail stones more than 19 mm Property damage Crop damage

Heavy rain 80% probability of precipitation greater than 50 mm over 24 hours Very low visibility and slippery roads Dangerous road conditions May flood low lying areas

Flooding Damage to property Raging rivers Damaged infrastructure Erosion Inaccessible roads Debris

Maritime: Waves higher than 5 m, 7 m Abnormal wave height High waves Offshore Fishing Industry drilling

Maritime: Tropical cyclones Lightning Storm Surge Huge waves Heavy rain and flooding

Aviation: Large Hail

Aviation: Severe Turbulence and Mountain waves

Aviation: icing and Ice accretion

Aviation: Volcanic Ash

Regional Specialist Meteorological Centre Heavy rainfall Strong Winds

Early warning Strive to ensure that every person or organization at risk • Receives the information • Understands the information • BELIEVES the information • Personalizes the risk • Make correct decisions • Respond in a timely manner

Early warning Effective early warning should be: • Short, concise, understandable and actionable • What, where, when, why, how to respond Should be presented in several different formats – text-graphics-color coded categories-audio; should included specific actions for people to take to respond to the event.

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