TEMPO.CO, Jakarta - Hail and tornadoes are natural weather phenomena that commonly occur during the transition season from dry to rainy seasons. Last Saturday, hail showered several areas in Cianjur, West Java and Situbondo, East Java, coupled by tornadoes.

The head of the Meteorology, Climatology and Geophysics Agency of Bandung chapter, Tony Agus Wijaya, said hail and tornadoes potentially occured in the transition period. "Or in the rainy season after several sunny days," said Tony Monday, November 19.

Read: 6 Ways to Better Prepare for Rainy Season

According to Tony, both local phenomena briefly occur on gray or black clouds of Cumulonimbus (CB) in a large and high volume. "The cloud passes through the frozen layer in the air at an altitude of about 4 kilometers," he explained.

Based on a BMKG release, Indonesia has currently entered the rainy season, which is evident in cloudy sky and rainfall almost every day—yet sunny weather can still shine on. In Bandung, for example, the weather was sunny since last weekend sans rain for three consecutive days.

Read: 7 Ways to Cope with Extreme Seasonal Transitions

Such weather conditions have raised questions on social media as to whether the rainy season has started or the transition phase was still on. Tony continued to explain the Bandung Raya area has now entered the rainy season but daily rains were not a must. "There are dynamic patterns of wind that make the rain clouds to fall or spread," he noted.

ANWAR SISWADI (CONTRIBUTOR)