Flash floods, which occur due to intense rainfall within a brief timeframe, recently struck Libya and Sikkim, India, causing significant devastation. While the Libyan flood was triggered by unprecedented rains and a rare storm named Medicane Daniel, the Sikkim flood had no prior forecast.

The Libyan catastrophe happened because of a storm called Medicane Daniel, which was like a hurricane in the Mediterranean Sea. This storm caused a lot of rain, which made dams in a usually dry area break and collapse. The breached Al-Bilad and Abu Mansour dams intensified the flood downstream, devastating areas until it reached the coast.

Key Attributes of Flash Floods:

• Flash floods result from rapid and heavy precipitation, often within a few hours, violently sweeping through riverbeds, streets, or mountain canyons.
• They can occur suddenly even without rainfall, such as after dam or levee failures or due to sudden water releases from debris or ice jams.

Flood Early Warning Systems (FEWSs):

• These systems play a critical role in mitigating floods by issuing timely alerts when a flood is imminent or underway.
• FEWSs comprise four vital components: understanding the at-risk areas, monitoring factors triggering floods, disseminating warnings effectively, and enabling effective community responses.
• While developed countries possess sophisticated FEWSs due to financial and technological capabilities, developing nations lag with less advanced systems. Nonetheless, advances in technology like remote sensing, artificial intelligence, and social media offer opportunities for enhanced FEWS capabilities.

Predicting Disasters:

Understanding Technologies and Challenges:

• Monitoring GLOFs (Glacial Lake Outburst Floods) includes using satellite observations, Doppler radars for cloudbursts, water level sensors, and geological sensors. These methods help detect vulnerabilities associated with such floods.
• Challenges include the lack of complete glacial lake maps and sensors, reducing preparedness.
• Flood predictions rely on weather stations, radars for rainfall, and river water level sensors, but improved observational data quality and accurate forecasting for small intense rainfall events are essential.
• Heatwave forecasts usually depend only on air temperature. However, a more effective approach involves using a combined heat index that takes into account humidity levels, especially in coastal regions.
• Predicting droughts relies on monitoring rainfall and soil moisture. However, the difficulty arises in combining data from various agencies to effectively manage droughts comprehensively.
• Cyclone forecasts use satellites, Doppler radars, and mooring buoys to predict their trajectory and intensity. However, improving sub-surface temperature data and enhancing models for rapid cyclone intensification remain challenges.

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Down to Earth Summary (November 01-15-2023)