Heavy rain and strong winds hit Jeju Island and southern coastal regions of South Korea this week as a low-pressure system moved eastward [1, 2].

The severe weather arrives just before the official start of summer, increasing the risk of safety accidents and flooding in mountainous and coastal areas.

Rainfall in the mountainous areas of Jeju Island already exceeded 300 mm [1]. Total accumulated rainfall in some areas is expected to reach approximately 500 mm [1]. The Korea Meteorological Administration issued heavy rain warnings, advisories, and strong wind alerts for Jeju and parts of the southern inland regions [2].

Wind speeds have been significant, with maximum instantaneous wind speeds exceeding 25 m/s [1]. The Korea Meteorological Administration said there is a possibility that intense rain will concentrate at rates between 10 and 30 mm per hour [2]. Some reports indicated that hourly rainfall on the southern coast could reach up to 50 mm [1].

Local authorities are monitoring the situation as the low-pressure system continues its path. The combination of high precipitation and wind has prompted emergency alerts to prevent casualties and property damage across the affected provinces [2].

"Jeju Island has been issued heavy rain warnings and advisories, and strong wind alerts simultaneously, which have also been extended to some inland areas including the southern coast," YTN News said [2].

“Rainfall in the mountainous areas of Jeju Island already exceeded 300 mm.”

The occurrence of such high rainfall totals in May suggests an early and intense start to the rainy season. When precipitation reaches 500 mm in a short window, it significantly increases the risk of landslides in mountainous terrain and coastal flooding, placing a heavy burden on regional disaster management systems before the peak summer months.