On November 21/22, 1938 the Ravine Poisson Landslide occurred causing 100 deaths.

Source: https://goo.gl/1qaiu6

On 27 September 2016, an area of inclement weather in the Atlantic Ocean began to gather speed, reaching speeds of 60 mph (96 km/h); by 11:00am Eastern Daylight Time (EDT) that same day, authorities in St Lucia issued a Tropical Storm Warning as the system had been upgraded to Tropical Storm Matthew, and it was expected to impact the island. Within hours of the warning, residents began to experience heavy rainfall and strong winds of up to 60 mph or higher associated with the approaching storm.

The intense northern eyewall passed over St. Lucia (Fig. 4). Tomas was at its peak intensity of 85 kt during that time. Tomas produced phenomenal rainfall in St. Lucia, with totals ranging from 21 to 25 inches and a maximum total of 26.3 inches from Desraches over about a 23-h period.