Hybrid Real-Idealized Tropical Cyclones as a New Loss Tool

Damages caused by Tropical Cyclones are amongst the highest associated with natural disasters. Tropical cyclone related wind (and associated storm surge) and precipitation damage is responsible for the largest portion of financial and material losses. From a reinsurance, management and building code perspective, it is therefore essential to assess the associated long-term risks. Traditionally, this long-term risk assessment is done through a 2-tier approach: 1) assessing wind and precipitation probabilities from historical meteorological observations, and 2) feeding these data into loss or impact models.

The shortcoming with this approach is the lack of an accurate and long historical record and the potential effects of climate change or long-term variability. Synthetic tropical cyclone tracks have traditionally been used to fill in the sparse available data. These have proven to be a useful and effective tool, but they lack information on important processes (e.g. interactions with complex terrain) and miss the combined effects of storm-surge and rainfall-flooding.

Here we describe the development of a new hybrid modeling capability based on the WRF hurricane model that has been designed through industry and (re)insurance collaboration to supplement the traditional statistical-synthetic approaches. The use of the system will be demonstrated using Townsville and Cairns as example locations.