At least six students were killed and five are still missing after heavy, drenching storms produced flash floods on the Indonesian island of Java on Friday.

The victims were a part of a large group consisting of about 250 students and teachers that was conducting scout activities along the Sempor River in the Sleman district of Yogyakarta, according to The Straits Times.

Rescuers search for victims following a flash flood in Yogyakarta, Indonesia, Friday, Feb. 21, 2020. The flash flood hit hundreds of students and teachers who were hiking along a river on Indonesia's main island of Java, killing a number of students, officials said. (AP Photo)

The Associated Press reported local military chief Lt. Col. Diantoro told TVOne that six victims were found a short distance down the river from the site of the flooding.

Areas of rain and thunderstorms popped up across the region through Friday afternoon, including the island of Java, where Yogyakarta is located.

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Since Indonesia straddles the equator and is surrounded by warm, tropical waters, the sudden downpours can quickly cause flooding, according to AccuWeather Senior Meteorologist Dave Houk.

Widespread rainfall totals of 25-50 mm (1-2 inches) were reported across the island, including the capital city of Jakarta on the western end of Java. Tropical moisture being forced up into the mountains of the island could have caused higher totals along the slopes and in the peaks of the mountains.

Rescuers look at a flooded river following a flash flood in Yogyakarta, Indonesia, Friday, Feb. 21, 2020. Hundreds of schoolchildren and teachers on an outdoor course were hit by the flash flood killing a number of children, a disaster official said. (AP Photo)

"Heavy rain upstream into the mountains can result in a rush of water down through rivers and streams," added Houk.

The quick rise in river levels and strong current swept some students away, National Disaster Mitigation Agency spokesman Agus Wibowo in a statement.

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According to the AP, citing Wibowo, the group wasn't paying attention to the weather conditions.

About two dozen students were injured in the flood and taken to a Yogyakarta hospital after being rescued.

These rapidly changing weather conditions are not uncommon in this region. Abundant tropical moisture can cause rain and thunderstorms to develop across the islands each day with occasionally heavy downpours.

"Indonesia is in the midst of the wet season which typically doesn't wind down until March or April," Houk said.

Rescuers shine torch lights as they search for victims following a flash flood in Yogyakarta, Indonesia, Friday, Feb. 21, 2020. The flash flood hit hundreds of students and teachers who were hiking along a river on Indonesia's main island of Java, killing a number of students, officials said. (AP Photo)

Scattered showers and thunderstorms can return to the area as the search for the missing students continues in the coming days.

"Some [storms] will be slow moving with heavy rain. So, typical of the season, flooding will remain a risk," warned Houk.

Earlier this year, downpours caused flash flooding and landslides in the Jakarta region, killing 53 people.

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