1.2 - Weather Hazards
The relative nature of extreme weather across different regions
Extreme weather is not a universal concept; it varies significantly depending on the location. What is considered extreme in one area might be entirely normal in another due to differences in climate, geography, and local adaptation.
Factors influencing perceptions of extreme weather
- Regional baselines - Normal weather conditions in one region can appear extreme elsewhere. For instance, typical rainfall in a wet region might be seen as excessively high in a drier area.
- Temperature norms - Average winter temperatures in a cold country could be viewed as unusually harsh in a warmer country with milder winters.
- Contrasting climates - Comparing countries with different weather patterns highlights how the definition of 'extreme' is relative and context-dependent.
Temperature variations and extremes in tropical and temperate climates
Temperature extremes differ markedly between tropical and temperate regions, influenced by their geographical positioning and seasonal patterns.
Typical and extreme temperature ranges
- Tropical regions - Located closer to the equator, these areas experience hotter summers with average highs around 33°C. Temperatures exceeding 40°C are deemed extremely hot.
- Temperate regions - Found in mid-latitudes, these regions have cooler summers with average highs near 23°C. Temperatures above 30°C are considered extremely hot.
- Summer differences - Tropical summers are generally about 10°C warmer than those in temperate zones.
- Extreme summer thresholds - In both regions, extreme summer temperatures are typically around 7°C higher than their respective averages.
Precipitation differences and extreme conditions in arid and temperate maritime regions
Precipitation levels vary widely between arid and temperate maritime regions, with significant implications for what constitutes extreme wet or dry conditions.
Precipitation patterns and extremes
- Arid regions - Characterised by low rainfall, these areas have an average annual precipitation of about 465 mm. Extremely wet years see rainfall above 550 mm, while extremely dry years can have less than 360 mm.
- Temperate maritime regions - These wetter areas receive an average annual rainfall of approximately 1150 mm, more than double that of arid regions. Extremely wet years exceed 1210 mm, and extremely dry years fall below 950 mm.
- Comparative extremes - The threshold for an extremely wet year in arid regions is far lower than in temperate maritime areas, reflecting their baseline dryness.
Wind patterns and extreme wind events in tropical and temperate areas
Wind strength and frequency of extreme wind events differ significantly between tropical and temperate regions, often due to the influence of specific weather systems like tropical cyclones or gales.
Characteristics of wind extremes
- Tropical regions - These areas are prone to powerful winds, especially during tropical cyclones, with speeds often exceeding 118 km/h. The strongest recorded wind in such a region reached 407 km/h.
- Temperate regions - Strong winds, known as gales, are less frequent, with speeds over 62 km/h occurring only a few days each year in most areas. The strongest recorded wind in coastal temperate zones hit 229 km/h.
- Impact of weather systems - Tropical cyclones in warmer regions drive far stronger winds compared to the gales experienced in temperate climates.
How were these notes?