Initially only accompanied by flaring convection, the system persisted in a region of low wind shear and strong outflow which promoted gradual development.

[3] A large central dense overcast developed over the low early on 3 April, prompting the Joint Typhoon Warning Center (JTWC) to issue a Tropical Cyclone Formation Alert.

[4] After moving away from Papua New Guinea, Ita underwent explosive intensification and attained its peak intensity as a Category 5 severe tropical cyclone early on 11 April.

Winds were estimated to have reached 220 km/h (140 mph) alongside a minimum central pressure of 922 mbar (hPa; 27.23 inHg).

Turning to the south-southeast, the storm weakened somewhat before making landfall near Cape Flattery as a Category 4 later on 11 April.

An automated weather station on Lizard Island, roughly 5 km (3.1 mi) from the storm's centre, recorded a pressure of 954 mbar (hPa; 28.17 inHg).

Maintaining gale-force winds the storm turned southwest and accelerated, eventually moving offshore north of Mackay on 13 April.

On 17 April, the low-level circulation center of the storm collapsed, as Ita affected New Zealand, bringing heavy rainfall and powerful winds.

[9] The Matanikau River, which runs through the capital city Honiara, broke its banks on 3 April and devastated nearby communities.

"[11] According to Permanent Secretary Melchoir Mataki, the majority of homes destroyed in Honiara were built on a flood plain where construction was not allowed.

[15] Ahead of Ita affecting Papua New Guinea, the National Weather Service issued tropical cyclone warnings for all island and coastal communities in Milne Bay Province.

[16] All schools and businesses were closed for several days in Milne Bay while residents were urged to remain indoors.

[17] The storm brought unusually heavy rains and strong winds to Milne Bay Province and the National Capital District.

[20] Officials in Milne Bay Province stated that 1,159 homes were destroyed by the storm; however, local authorities claimed thousands more collapsed.

As Ita neared landfall, all residents in Cooktown and Hopevale were advised to evacuate either to a community cyclone shelter or to leave the towns.

[24] Though a weakened storm at landfall, Ita brought damaging winds to coastal areas around Cape Flattery where gusts peaked at 160 km/h (99 mph).

Minor flora damage was reported at Mackay, in the heart of city the top of a palm tree was blown off by the high winds.

[35] The greatest losses took place in the agricultural sector, with a 700 km (430 mi) stretch of sugarcane country suffering damage.

Agricultural damage in parts of the South Island were compared to Cyclone Bola in 1988, a storm regarded as one of the worst to ever strike New Zealand.

[44] Debris left behind by the floods initially hampered relief efforts, with the runway at Honiara International Airport blocked by two destroyed homes.

[53] On 15 April, Papua New Guinea Prime Minister Peter O'Neill and Speaker of Parliament Theo Zurenuoc provided PGK300,000 (US$113,700) in funds to Milne Bay Province.

The nation's health office also warned of the dangers of post-storm diseases due to damaged sewer systems.

[56] Owing to the severity of agricultural damage, the average cost of avocados, bananas, iceberg lettuce, and papayas increased.

[63][64] Though the earthquakes only produced a localised tsunami, with limited effects,[65] they prompted evacuations and delayed relief efforts across the Solomon Islands.