The United States Armed Forces through the Joint Typhoon Warning Center (JTWC) and Naval Pacific Meteorology and Oceanography Center (NPMOC), also monitored the basin and issued unofficial warnings for American interests.

TCWC Nadi, Brisbane and Wellington measured sustained windspeeds over a 10-minute which are compared to the modern day Australian tropical cyclone intensity scale.

The JTWC and the NPMOC measured sustained windspeeds over a 1-minute period which are compared to the Saffir-Simpson Hurricane Scale (SSHS).

[3] The island of Tatafa was bisected by a 16 metres (52 ft) wide channel caused by Isaac's storm surge.

Between February 4 - 5, a developing tropical cyclone existed to the west of the Samoan Islands and caused flooding, as well as widespread wind damage within American Samoa.