Issuing disaster warnings :

Changing weather patterns to be considered

by Dhaneshi Yatawara

With sudden changes in weather patterns during the inter-monsoon season, long-term warnings on natural disasters cannot be issued, authorities say.

“The intensity of rain largely varies in this climate. So it is difficult to give a long-term prediction,” said Head of Landslide Studies and Services Division of the National Building Research Organisation (NBRO) R.M.S. Bandara. Warnings on natural hazards will be issued by the authorities, taking into consideration the changes in weather patterns.

As a result, it is important for the public and local authorities to be aware of signs to identify the degree of risk in their localities from natural hazards.

According to NBRO guidelines, in severely disaster prone areas which are graded as prohibited areas, local authorities should make every effort to avoid settlement development.

In moderately prone areas, precautions as described under NBRO guidelines need to be followed.

Where necessary, on the advice of the local authority, geo-technical investigations may have to be done through an agency such as the NBRO or Civil Engineering Departments of the Moratuwa and Peradeniya Universities.

According to NBRO guidelines, a flat land is with a maximum slope of five degrees angle– a gentle slope. A moderate land has a 5 to 31 degrees of slope angle and constructions are allowed only with methods to mitigate a possible hazard as approved in the NBRO guidelines. On a land with a slope angle over 31 degrees, no constructions are allowed.

It is compulsory to ensure that a particu lar land demarcated for constructions is hazard-free. The public and the construction sector need to be aware of signs of hazard in a land to be used for any construction.

The sudden opening and progressive widening of cracks on the slope surface or walls of buildings close to the site, progressive tilting of trees and towers on the slope, sudden oozing or appearance of water on the slope and continuous water logging due to poor slope drainage, subsidence and/or heaves on the slope, subsidence of roads and bulging of sides retaining walls of roads are some of these danger signs.