During ENSO events, there are likely to be drier than normal periods. Rainfall has generally been associated with tropical storms that may be more likely to generate in the region during ENSO.  The strength of the El Niño event has some effect on the precipitation, and some ENSO signals have been wetter than normal. 

With a few exceptions, American Samoa did not show any significant variations in sea level during the strong and moderate El Niño years.  In contrast, La Niña years showed two distinct scenarios.  During strong La Niña years, sea level was lower than average.  During moderate La Niña years, sea level was higher than average.  The deviations were most pronounced from February to July during both strong and moderate La Niña years [1].

View above Pago Pago Harbor Source: C. Anderson, 2005. View of Pago Pago Harbor entrance from the nearby ridgeline at the Falepule Hotel and Restaurant.

White-collared kingfisher. Source: Athena Pratt. NRCS.

Heavy showers and long rainy periods can occur in any month while typhoons are common from December to March [2]. Tropical cyclones impact the island chain with tropical storm-force winds once every three years, on average [9]. In 2003, heavy rainfalls resulted in severe landslides and flooding, for which a Presidential Disaster Declaration was made [2]. Tropical Cyclone Heta in 2004 and Tropical Cyclone Olaf in 2005 resulted in disaster declarations with flooding, high surf, and high winds [3]. The prevailing winds throughout the year are easterly trades, interrupted more often in summer than winter, and sometimes associated with tropical cyclones, convergence bands, and upper level disturbances.

Gathering of Matai to celebrate Samoa Flag Day. Source: American Samoa Coastal Management Program. 2003

American Samoa has several climate sensitive sectors that provide livelihood for the people, including the tuna canneries that are the primary economic resource and marine and coastal ecosystems.  American Samoa developed a climate change working group within the Coral Reef Advisory Group to monitor impacts of changes on coral reef ecosystems.  During the Stakeholder Workshop, the Government described a commitment to developing a climate change adaptation strategy that would support community-based adaptation measures in the villages (See Page Stakeholder Dialogue, American Samoa Summary Report, 2006). Understanding that the natural environment contributes to their livelihood, the American Samoa Government has formed many environmental task forces and initiatives to promote sustainable development of resources for long-term survival of their people.