Cyclone Nancy originated out of a broad area of low pressure within a monsoonal trough northeast of Samoa on February 10.

[1][2] Initially, the system was nearly stationary within an area of weak steering currents, low wind shear and high sea surface temperatures, exceeding 30 °C (86 °F).

By 0600 UTC on February 12, the system's outflow improved and a small area of deep convection, known as the central dense overcast, developed over the center of circulation.

[1] By this time, the Joint Typhoon Warning Center (JTWC) had also begun issuing advisories on the storm, designating it as Tropical Cyclone 18P.

[2] Convective banding features developed close to the center of circulation as the storm began to undergo explosive intensification.

[1] The JTWC, however, assessed Nancy to have been substantially weaker until 0000 UTC on February 14, at which time they reported a 95 km/h (59 mph) increase in winds, attaining minimal Category 3 status on the Saffir–Simpson hurricane scale.

By February 16, Nancy weakened below hurricane intensity and turned to the southwest as it began to undergo a Fujiwhara interaction with Cyclone Olaf to the north.

[1] Strong shear associated with the outflow of Cyclone Olaf caused all convection associated with Nancy to be displaced to the southwest on February 16.

A gale watch was declared for Samoa and strong wind warnings were raised in Tuvalu, Tokelau and the Cook Islands.

[10] Already impacted by Cyclone Meena just a week prior, residents in the Cook Islands heeded warnings and evacuated to emergency shelters.

[11] Coastal areas where seawalls had been damaged or destroyed by Meena were of particular interest to warning centers and urged all people in the vicinity of them to evacuate to a nearby shelter.

[18] Several homes had their roofs blown off, coconut trees were downed, road were covered in debris and heavy rains fell throughout all the islands.

[19] Damages caused by the storm to the Avana Marina Condominiums forced the owners to close them until mid-April to allow for reconstruction and renovation.

The Red Cross provided relief items, such as blankets and lanterns worth $35,200; the Pacific Forum provided food, fuel, and logistical support worth $32,000; the Government of China donated $19,200 in post-disaster funds; $32,000 in funding was provided by the United Nations Development Programme; contributions from the Australian Agency for International Development and the New Zealand Agency for International Development amounted to $862,570, consisting of fuel, shelter, relief items, and disaster funds; the Government of Australia provided $128,000 wort of fuel and equipment; lastly, the Government of France deployed military teams with recovery supplies and tents.