Commonwealth of the Northern Mariana Islands (CNMI)

The Northern Mariana Islands are considered the sunniest islands in Micronesia [3]. The islands have a tropical marine climate moderated by seasonal northeast trade winds from November to March and easterly winds from May to October. Average year-round temperature is 84° F (28.9 °C) with an average humidity of 79%. The ocean temperature averages 82° F (27.8 °C). There is little seasonal temperature variation. Temperature, however, is affected by elevation; hence, the islands of Saipan and Rota show considerably greater temperature variations between the coastal and mountainous areas [5]. The dry season runs from December to June, and the rainy season from July to November [4]. Average yearly rainfall is 50 inches (130 cm) per year [6].

Struggling to Manage Utilities in CNMI during Typhoons
CMNI is located in the infamous Typhoon Alley, directly north of Guam. This puts the territory at risk on a routine bases for very powerful storms. In addition to storms, Saipan, Tinian, and Rota are also subject to earthquakes. Following a review of CNMI's hardening of the utility generation, transmission, and distribution system, it is clear that CNMI has a long way to go before it has completed the hardening process. Many of the power distribution poles are wood. This type of pole routinely fails during heavy winds. The newer pre-stressed concrete poles provide for a more reliable system during typhoons. In addition, there are heavy-duty insulators that can be used to prevent lines from breaking the insulators during typhoon condition winds. Based on discussions with the CNMI utility management, there are no funds available to continue the hardening effort. With the high fuel prices, low rates, and high system losses, the utility is struggling to be able to meet payroll and maintain the system assets [6].

Damage on Rota by Supertyphoon Pongsona.
Source: Andrea Booher, FEMA News Photo.
Rota, Commonwealth of Northern Mariana Islands (CNMI), December 20, 2002 --The island of Rota received a Presidentally declared disaster declaration after receiving widespread damages from Supertyphoon Pongsona.

 

Large-scale tourism drives the economy, and many of the tourist visit to see the natural beauty of the Northern Mariana Islands, which is highly dependent on climate.

CNMI sunset. Source: C. Anderson, 2006.
Tourism is the primary industry of local economy. Tourists visit Saipan for its beautiful beaches, sunset views, and marine recreational activities, such as sportsfishing, diving, snorkeling, and kayaking.

 

  

The west coast of Saipan, the most populated area in CNMI, is protected by a fringing barrier reef, while the relative absence of reefs on the east make that side of the island subject to strong waves fed by the tradewinds, particularly during Saipan’s winter (November to April). The Commonwealth is situated some 600 miles (966 km) east of an area in the western Pacific which is the breeding area of cyclonic disturbances. As a result the Commonwealth is in what is known as weather condition four at all times which means that 40 mile (64 km) an hour winds are possible within 72 hours [5]. These cyclonic disturbances can quickly and sometimes unexpectedly develop into typhoon force winds of 120 miles (193 km) per hour or greater. Typhoon season runs from July to January, and the islands of the CNMI are usually subject to at least one typhoon each year [5]. Flooding and wind damaged vegetation are a common result of frequent storms with winds above 60 mph (97 kph)[6].

Sometimes the islands experience droughts from low rainfall during the period from December through June [5], and have experienced drought during strong ENSO events, although not as severely as many other islands in Micronesia. During the 1997-1998 ENSO event, the island implemented water conservation measures. Since tourism is a large driver of the local economy, the hotels used desalination units to ensure that guests had enough water and acted as a backup resource for critical facilities, such as the hospital. Alternatively, there has been frequent flooding in low-lying coastal areas and roadways of Saipan during heavy rainfall, which required drainage improvements and flood mitigation planning. The Northern Mariana Islands recognized the need to include climate-related hazards in the update of their hazard mitigation plan. (See Stakeholder Dialogue, CNMI Summary Report, 2006).

 

Typhoon Pongsona in CNMI
On December 8 and 9, 2002, Rota, the southernmost island of the CNMI was hit by Typhoon Pongsona. The typhoon produced sustained winds of 78 mph (126 km/h ) with gusts to 85 mph (137 km/h ). The combination of winds and other effects from the typhoon destroyed 114 houses, severely damaged 154, and caused minor damage to 306 houses. About 200 families were left homeless. The typhoon produced a storm surge of 6.7 m (22 ft) at the largest and most populated Songsong Village of the island. The surge caused moderate beach erosion on the island, and destroyed a fuel pier and a loading pipeline. Additionally, the typhoon caused severe crop damage on the island. The typhoon resulted in over $30 million in damage (2002 USD, $34 million 2007 USD) [7].

 

Small increases in temperatures could result in large impacts to coral reefs, and subsequent impacts to the marine and coastal environment. Landfills to support the increase population on the island have resulted in groundwater contamination on Saipan, which might contribute to disease [4], and has conflicted with environmental conservation and endangered species protection [1]. There is recognition that environmental degradation and stressors will exacerbate the impacts from variations and changes in climate. (See Stakeholder Dialogue, CNMI Summary Report, 2006).


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