APCEDI Alert 13P, Cyclone Ivy #12, 2004

Dear Colleagues

Alert 12, Cyclone Ivy 13P / 25 February 2004, Sydney 2200 EDT

Cyclone Ivy has weakened slightly, and the eye has been filled in by a large area of deep convection similar to the situation in the earlier history of the storm. It is now a weak Category 2 storm. The central core of deep convection reaches from the Banks Group in the north to Epi in the South and covers all the large Northern Islands and adjacent islets. The centre of this core is just to the west on the main city of Lonorore on the island of Pentecost. Ivy is still slow moving but is forecasted to pick up some forward speed toward the south in the next 6 hours.

Torrential rains continue over the southern Banks Group, Santo, Malakula, Maewo, Pentecost, Ambrym, Ambae and Epi. Intermittent heavy rains are over the Shepherd Islands, Efate and the capital Vila. Due to the slow forward speed of Ivy, this torrential rainfall situation will continue into tonight and tomorrow throughout Northern and Central Vanuatu.

Inner feeder bands with severe gales and heavy rains continue to effect Anuta and Tikopia with more heavy rain having recently again moved into Vanikolo and the Torres Group. Further to the north, the weather over Nendo and the North Santa Cruz continues to improve.

Most predictive models continue to forecast Ivy tracking southerly across the length of Vanuatu throughout the next 24-36 hours and then on to New Caledonia. The official track out of the JTWC has Ivy moving over the Northern Islands this evening to just west of Vila tomorrow morning 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 from the Banks Group south and for Anuta and Tikopia in the Solomons. The APCEDI alerts for the Santa Cruz Group and the Torres have been lifted. However, isolated, intermittent heavy showers are still likely. In fact more heavy rain from feeder bands is again entering this northern area tonight. If the eye feature maintains it current course, it will continue to pass to the west of Pentecost and would be over Ambrym or Southern Malakula in about 4-6 hours.

The current situation is summarised as follows:

Possible Damaging Category 2 Eyewall-strength Gales and Torrential Rains
Vanuatu
Maewo (Entire Island)
Pentecost (Entire Island)
Ambae (Entire Island)
Santo (East and South Coast)
Malakula (East and South Coast)
Ambrym (Entire Island)

Damaging Sustained Category 1-2 Gales and Heavy Rain
Vanuatu
Mere Lava (but soon decreasing)
Santo (West Coast)
Malakula (West Coast)
Epi (Entire Island)

Sustained Gales and Heavy Rain with approaching damaging hurricane force in the next 4-6 hours
Vanuatu
Efate
Shepherd Islands

Sustained Gales and Heavy Rain approaching damaging hurricane force in the next 6-10 hours
Vanuatu
Erromango
Tanna
Anatom

Intermittent Gales and Heavy Rain associated with Inner Feeder Bands (Storm now moving away)
Vanuatu
Banks Group
Torres Group
Solomons
Tikopia
Anuta
Vanikolo

Given the continuing Category 2 nature of the storm, damage overall at this time should be moderate and localised. However, the danger from flash-flooding is increasing. As Ivy continues to be so slow moving, this will likely result in very heavy widespread 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 storm continues to pass slowly or even stalls. Locally moderate to severe damage will also likely occur near to the centre of the storm. Varying degrees of crop damage are also likely. Seas will be very rough to phenomenal resulting in tidal flooding of low-lying areas. If a central eye wall manages to re-emerge later tonight, and the storm strengthens, damage along its path will certainly be more severe.

Larger Vanuatu Islands
The centre of Ivy is now west of Pentecost. Torrential rains and damaging Category 1-2 gales have been pounding Maewo, Pentecost, Ambae, Santo, Ambrym and Malakula for most of the day and will continue for most of the night. This rough weather had moved into Epi and the Shepherds since this afternoon, and the situation is now deteriorating in Efate and Vila tonight. The slow moving nature of the storm mean that rainfalls in the hundreds of millimetres will have been registered throughout the region and will be continuing. This will certainly be causing flash flooding of many stream valleys and larger rivers. The situation in hill and mountain areas of Santo, Malakula, Ambae, Pentecost and Ambrym is of particular concern. 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. This may be difficult as Vila itself will be under the gun much of tomorrow. In addition to flash flooding, coastal flooding and wind damage can be expected at least in localised areas near the centre.

Banks Group
The centre of the storm is finally moving away from Mere Lava and the rest of the Banks Group. The whole group has had very heavy rains, very rough seas and increasingly severe winds for almost 36 hours. With the centre having slowly moved over Mere Lava, this outer island may be particularly hard hit. With the cyclone pulling away from this Group, assessments should be done of the areas to determine the degree of wind damage and flooding. Crops are likely badly affected in some areas.

Anuta and Tikopia, Solomons
Anuta and Tikopia are now out of the centre of the storm but unfortunately still continue 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 36 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.

Torres Groups, Vanuatu and Santa Cruz Group, Solomons
Inner feeder bands with heavy rains and squalls are now beginning to break up and subside over the region. Seas will remain very rough. The Torres Group, Vanikolo 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.

General Alert
Authorities in Vanuatu from the Banks Group 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 Anuta and Tikopia in the Eastern Solomons should continue 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