The death toll of Sri Lanka's recent floods and landslides is set to rise as many areas remain unreachable due to continuous rain, collapsed roads and unstable terrain.

A state of emergency is announced as Sri Lanka grapples with its worst weather disaster in years.

For villages on the northern edge of Sri Lanka's capital, floods are a familiar ordeal -- but even the hardiest residents were stunned when the Kelani river surged this week.Heavy showers upstream inundated the banks of the Kelani on Friday night,

Hundreds more are missing following flooding and landslides in the past week, which killed at least 502 people in Indonesia, 334 in Sri Lanka and 170 in Thailand, authorities said.

Officials in Indonesia and Sri Lanka battled Wednesday to reach survivors of deadly flooding in remote, cut-off regions as the toll in the disaster that hit four countries topped 1,300.In Indonesia, there is growing frustration among survivors of catastrophic flooding and landslides over the pace of the rescue effort and aid delivery.

Severe flooding that ravaged communities across Sri Lanka was visible from space, as seen in satellite imagery released by a US-based research institute.Imagery posted by the Cooperative Institute for Research in the Atmosphere at Colorado State University shows the difference in terrain between November 2 and November 30 after the flooding hit.

Hundreds more were still missing and millions have been displaced in the rain-drenched region, with Sri Lanka and Indonesia hit particularly hard.

Nepal has extended an economic aid of USD 200,000 for relief and rescue operations in flood-hit Sri Lanka, underlining that it stands firmly with the island nation in this difficult time.