Spain:
periodic droughts

Spratly Islands: typhoons; serious maritime hazard because of numerous reefs and shoals

Sri Lanka:
occasional cyclones and tornadoes

Sudan:
dust storms

Suriname:
NA

Svalbard:
ice floes often block up the entrance to Bellsund (a
transit point for coal export) on the west coast and occasionally
make parts of the northeastern coast inaccessible to maritime traffic

Swaziland:
NA

Sweden:
ice floes in the surrounding waters, especially in the Gulf
of Bothnia, can interfere with maritime traffic

Switzerland:
avalanches, landslides, flash floods

Syria:
dust storms, sandstorms