APCEDI Alert 13P, Cyclone Ivy #9, 2004

Dear Colleagues

Alert 9, Cyclone Ivy 13P / 25 February 2004, Sydney 0800 EDT

Cyclone Ivy has strengthened overnight and has begun its decurvature to the south. It is now a borderline Category 1-2 Cyclone moving southwest at 5 knots. The eye feature is still not clear, but the central core of convection extends from the Banks Group in the North to Santo in the west to Pentecost in the south. The deepest convection, and thus very heavy sustained rain and gales is over Mere Lava and Northern Maewo.

On its current track this central area of deep convection will be moving over most of the big northern islands and be centred between Malakula and Ambrym in 6-12 hours.

Inner feeder bands with severe gales and heavy rains continue to effect Anuta and Tikopia, the Torres Group and most of the Santa Cruz Group. However the storm should be clearing from these areas in the next 6-12 hours if it maintains its more southerly course.

Most predictive models are now showing Ivy tracking southerly across the length of Vanuatu throughout the next 24-48 hours.. The official track out of the JTWC has Ivy moving over the Northern Islands to just west of Vila tonight as a Category 2-3 storm and then on to the Loyalty Islands and New Caledonia tomorrow as a Category 3. As such, the APCEDI warnings will continue all of Vanuatu north of Efate and all the Santa Cruz Group and will be extended to include Southern Vanuatu Islands of Erromango, Tanna and Anatom.

The current situation is summarised as follows:

Damaging Sustained Category 1-2 Cyclonic Gales and Heavy Rain
Vanuatu
Banks Group
Maewo
Pentecost
Ambae
Santo
Ambrym
Malakula

Sustained Gales and Heavy Rain approaching damaging Category 1 force in the next 3-8 hours
Vanuatu
Epi
Shepherd Islands
Efate

Intermittent Gales and Heavy Rain associated with Inner Feeder Bands (Storm now moving away)
Vanuatu
Torres Group
Solomons
Nendo
Nupani
Duffs
Swallows
Tikopia
Anuta
Vanikolo
Utupua

Alert for Increasing Threat of Gales and Heavy Winds tonight and tomorrow
Vanuatu
Erromango
Tanna
Anatom

Given the continuing Category 1-2 nature of the storm, damage at this time should be light to moderate and localised. However, locally moderate to severe damage could occur near to the centre of the storm. Main threats will continue to include lowland tidal flooding and flash-flooding in hill areas. Some crop damage is also likely. As Ivy continues to be slow moving, this will likely result in heavy localised rainfall which could result in flash-flooding of mountain and hill areas as well as known flood prone areas. This is especially critical for the large Vanuatu Islands particularly Santo. Due to the islands’ very high relief and the slow movement of the storm, flash flooding will be a major threat throughout tonight and tomorrow especially if the the storms passes over the islands slowly or even stalls. If a central eye wall manages to emerge later tonight, and the storm strengthens to Category 2-3, damage along its path will certainly be more severe.

Anuta and Tikopia, Solomons
Anuta and Tikopia are now out of the centre area of the storm and in the inner feeder bands. Gales and heavy rains should start subsiding in the next 6 hours and become more intermittent and less severe after this. Light to moderate damage caused by tidal flooding of low-lying areas, crop damage and possibly some damage to unstable structures is expected given the nearly 24 hours of punishment by this storm. However, the overall damage will not be anywhere as bad as with Cyclone Zoe. However, the cumulative effects of 3 major cyclones in 14 months (Zoe, Gina and now Ivy) may well be wearing down the ability of the people and their environment and its resources to sustainably cope. NDMO and Donors should endeavour to make contact with the islands to assess both the immediate effects of Ivy and cumulative effects of the last 3 storms on the overall situation.

Banks and Torres Groups, Vanuatu
With the cyclone pulling away from these groups in the next 6-12 hours, a general survey should be done of the areas to assess the degree of flooding which will likely be the major threat particularly on the larger Banks Islands and the more low-lying atolls. The eastern most island of Mere Lava should be assessed quickly tonight or early tomorrow since the centre of the storm has likely passed over or very close to this island.

Santa Cruz Group, Solomons
Vanilkolo and to a lesser extent Utupua have received very heavy rainfall from their proximity to this slow moving storm so some flooding may have occurred. They should be assessed later today. The remainder of the Group has likely only experienced minor coastal flooding, but contact to all the all the smaller outliers should be undertaken to verify this.

Larger Vanuatu Islands
GOV, NDMO and Donors should now prepare themselves for needing to make widespread assessments across most of the big islands of northern Vanuatu tomorrow and in the following days. While the Category 1-2 size of the storm should limit damage, coastal flooding, flash flooding in hill areas and wind damage can be expected at least in localised areas near the centre. Plans need to be made with the knowledge that the capital Vila is also likely to be effected by the storm.

General Alert
Authorities in Vanuatu from the Torres Islands to Anatom (including Torres and Banks Islands, Pentecost, Ambae, Santo, Malakula, Ambrym, Paama, Ulveah, Epi, Shepherd Islands, Efate, Erromango, Tanna and Anatom including all small islands in these areas) as well as all of the Santa Cruz Group in the Eastern Solomons should be on alert, monitor the path of the storm closely throughout tonight and tomorrow and take immediate actions to protect people and property. People in mountain areas along the eastern and southern slopes of ranges should be on alert for heavy rain resulting in flash flooding. Low lying coastal areas especially along east and southern parts of large islands should also be on alert for tidal flooding.

Concerns in New Caledonia including the Loyalty Islands should continue to monitor this storm as it develops over the next few days.

APCEDI will continue monitoring the event. More detailed information about the storm can be found on

https://metoc.npmoc.navy.mil//jtwc.html
http://www.met.gov.fj/advisories.html
http://www.nrlmry.navy.mil/tc_pages/tc_home.html

Kevin Vang
APCEDI Coordinator