Jeju uprising to Jeju from Busan and deploying police companies, each 1,700 strong, from the southern provinces of the mainland. The guerrillas retreated to their bases in the forests and caves around Hallasan, an extinct volcano and the highest mountain in South Korea. On April 29, the Korean, non-military, governor of Jeju province abandoned his post, defected, and joined the guerrillas. This caused many police officers, disillusioned by the atrocities they were ordered to commit against their own, to do the same. In response, U.S. military provincial governor William F. Dean ordered a purge of SKLP sympathizers from the ranks of the
Hallasan from the sea is formed on the coastal area and the peak temperature is mainly observed during the daytime. The change of the minimum temperature varies depending on the degree of cooling of Hallasan and the intensity of the wind speed.When the wind blows due to the predominance of sea breeze, the air cooled in Hallasan descends to the coastal area and induces the decrease in temperature. When the synoptic wind blows strongly, the cold air of Hallasan moves to the downwind side and the lowest temperature appears. The lowest temperature in the downwind area is 2 ~ 5℃ lower