Posted by: coastlinesproject | November 24, 2016

Hurricane Otto; Thanksgiving Surprise!

NewsALERT™
AIR WORLDWIDE

Otto Headed for Rare Thanksgiving Landfall
Current Location: 11.1°N, 80.7°W (as of 15:00 UTC)
Movement: West-northwestward at 5 mph
Maximum sustained winds: 70 mph
Minumum central pressure: 994 mb
Forecast track and intensity: Otto is projected to continue westward, restrengthen, and then make landfall on the eastern coast of Central America as a Category 1 hurricane in either Costa Rica or Nicaragua
AIR WORLDWIDE
on the morning of November 24, 2016; weaken due to land interaction as it moves across the peninsula over the following 24 hours; and eventually dissipate early next week after it emerges over the Pacific Ocean
Hurricane and tropical storm warnings: A hurricane warning is in effect for the Atlantic coasts of southern Nicaragua and the northern half of Costa Rica; a hurricane watch is in effect for the Atlantic coasts of central Nicaragua and southern half Costa Rica; a tropical storm warning is in effect for the island of San Andrés; a tropical storm watch is in effect for the Atlantic coast of the northern half of Panama and the Pacific coasts of the southern half of Nicaragua and northern half of Costa Rica
Other hazards: Precipitation-induced flood, flash floods, mudslides, and storm surge
Dominant construction types in area: Residential buildings in Costa Rica and Nicaragua are primarily of wood or masonry construction with clay tile, wooden, or metal roofs; commercial structures in Costa Rica and Nicaragua are primarily of masonry construction, followed by concrete construction; small industrial plants in Central America consist of multiple sets of buildings with different construction types, predominantly reinforced concrete, steel, and light metal; large industrial facilities in Central America consist of diverse classes of structures or components, including stacks, cooling towers, pipes, and tanks
Expected damage at forecast wind speeds: Non-engineered structures may experience some instances of damage to roof and wall claddings; isolated damage to engineered structures is possible; some damage to signage, traffic lights, and trees can be expected

ALERT™ subscribers can download similar stochastic event (SSE) IDs for Otto from the ALERT website.

A rare, late-season tropical cyclone, Otto is poised to make landfall as a Category 1 hurricane in either Costa Rica or Nicaragua on the morning of November 24, 2016—the U.S. holiday of Thanksgiving. As of November 23, 2016, a hurricane warning was in effect for the Atlantic coasts of southern Nicaragua and the northern half of Costa Rica, a hurricane watch was in effect for the Atlantic coasts of central Nicaragua and southern half Costa Rica, a tropical storm warning was in effect for the island of San Andrés, and a tropical storm watch was in effect for the Atlantic coast of the northern half of Panama and the Pacific coasts of the southern half of Nicaragua and northern half of Costa Rica.
Track map for Otto as of 15:00 UTC on November 23, 2016. (Source: NOAA)

Meteorological Summary

After reaching hurricane strength on the afternoon of November 22, 2016, Otto weakened to tropical storm status by the morning of November 23 with maximum sustained winds of 70 mph and a minimum central pressure of 994 mb. Currently moving west-northwestward at 5 mph, Otto is projected to restrengthen into a Category 1 hurricane before making landfall on the Atlantic coast of either southern Nicaragua or northern Costa Rica on November 24 and weaken as it moves across the Central American peninsula in the following 24 hours due to land interaction.

Prior to landfall, Otto’s outer rain bands are expected to bring 4–8 inches of rain to the island of San Andrés and the higher terrain of central and western Panama and southern Costa Rica through Wednesday. Through Thursday, rainfall totals in northern Costa Rica and southern Nicaragua are projected to reach 6–12 inches, with some areas receiving as much as 15–20 inches; life-threatening flash floods and mudslides are likely. Hurricane conditions due to strong winds are expected within the warning area and possible in the watch area on Thursday; tropical storm conditions are possible throughout the warning and watch areas of Nicaragua, Costa Rica, Panama, and San Andrés starting Wednesday evening. Storm surge could raise water levels 2–4 feet above normal tide levels in hurricane warning areas.
Hurricane and tropical storm warnings and watches for Otto. (Source: NOAA)

Central America faces the threat of tropical cyclones from both the North Atlantic and Northeast Pacific basins, with a higher frequency of landfall from Atlantic-based storms that typically form at sea and move westward toward land. Consequently, the Atlantic coastline—which is less developed than the Pacific coastline—has a higher risk of experiencing mature tropical cyclones that can cause significant wind and precipitation damage.

A tropical cyclone impacting Central America this late in the season is rare, but not unheard of. According to the NOAA Best Track Database, 18 storms of at least tropical storm strength have formed on or after November 21 since 1950, of which only nine became hurricanes in the Atlantic basin. A mere three hurricanes have made landfall in Nicaragua in November or later since 1842. If Otto makes landfall in Costa Rica, it would the first recorded for the country. According to the National Hurricane Center, Otto is the latest hurricane formation on record in the Caribbean Sea, edging out Martha (1969) by about a day.

Exposure at Risk

Central America’s most concentrated exposures are in urban centers, which consist mainly of capital cities and resort towns. The most at-risk exposures are in Pacific and Caribbean coastal cities. The rapid growth rate within Central American cities is exacerbating the risk in areas of high exposure concentration. Poor, rural families are migrating to cities at high rates and building poorly designed structures along city outskirts on urban slopes, thus increasing the risk of flooding in the surrounding low-lying areas often corresponding to urban centers. Building contents, including system equipment stored in basements or on first floors, are vulnerable to flood damage. Inland exposure concentrations are at risk from precipitation-induced flooding due to heavy rainfall, which may collect in low-lying areas and cause river- and streambeds to overflow and flood surrounding regions.

Residential buildings—defined as single-family homes, multi-family homes, and apartment buildings—in Costa Rica and Nicaragua are primarily of wood or masonry construction with clay tile, wooden, or metal roofs; wind damage to roof and wall claddings is possible in non-engineered structures. Masonry structures, such as low-rise apartment buildings, can better resist the wind uplift load than wood-frame buildings due to their mass. However, the type of masonry construction—masonry, unreinforced masonry, and reinforced masonry are represented in these countries—will impact performance against wind loads, with confined masonry structures generally experiencing the least damage. High-rise apartments buildings typically constructed to strict building codes will better resist wind damage, often limited to nonstructural components such as windows, wall siding, and roofs.

Masonry construction dominates commercial structures in both Costa Rica and Nicaragua, followed by concrete construction. Low-rise commercial buildings may experience roof and wall system damage from wind depending on construction type, whereas wind damage to well-engineered high-rise structures is likely to be limited to nonstructural elements. Small industrial plants in Central America consist of multiple sets of buildings with different construction types—predominantly reinforced concrete, steel, and light metal—which contain most equipment and will perform similarly to commercial exposures. Large industrial facilities in Central America consist of diverse classes of structures or components, including stacks, cooling towers, pipes, and tanks, located in a widespread open area, all of which perform differently in hurricane-force winds and flood.

Industry Impact

Costa Rica has the 68th largest non-life insurance market in the world, with automobile and property as the major business classes. Only about a third of domestic properties are insured in Costa Rica; the industrial, commercial, and tourism lines generate a reasonable amount of property business for the insurance sector. The Nicaraguan insurance market has one of the smallest markets in the region, and domestic property coverage remains low. Automobile is the largest class of non-life business, receiving almost half of premium income; property is the second largest class with around a third of premiums. Because the projected landfall location—in the northern part of Costa Rica or the southern part of Nicaragua—is sparsely populated with little development and the take-up rates for these countries are relatively low, insured losses from Otto are not expected to be significant.

Forecast Track

Otto is projected to continue westward, restrengthen, and then make landfall on the eastern coast of Central America as a Category 1 hurricane in either Costa Rica or Nicaragua on the morning of November 24, 2016. Otto is then expected to weaken due to land interaction as it moves across the peninsula over the following 24 hours and eventually dissipate early next week after it emerges over the Pacific Ocean.

ALERT subscribers can download similar stochastic event (SSE) IDs for Otto from the ALERT website. Unless the situation changes dramatically for this event, this will be our final posting for Otto.

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