Overall Green alert Tropical Cyclone for ZAZU-20
in Niue, Tonga

Impact

Tropical Cyclone ZAZU-20 can have a low humanitarian impact based on the maximum sustained wind speed,exposed population and vulnerability.

Meteorological source GDACS (JTWC)
Exposed countries Niue, Tonga
Exposed population No people in Category 1 or higher
Maximum wind speed 102 km/h
Maximum storm surge 0.2 m (15 Dec 01:00 UTC)
Vulnerability High (Niue)

GDACS Score

GDACS alert score for Tropical Cyclones is 0.5 (GREEN Alert), 1.5 (ORANGE Alert), 2.5 (RED Alert)
For more info on GDACS alert score click here.
  Wind Storm surge Rainfall GDACS score
GDACS Current 102 km/h 0.2 m n.a. 0.5
GDACS Overall 102 km/h 0.2 m n.a. 0.5

Maximum winds, storm surge, rainfall (Current: over the next 72 h, Overall: entire TC track)

Wind

102 km/h Current Max.

Up to 100000 people in Tropical storm (see SSHS)

Impact Timeline

Alert Date (UTC) Max Winds (km/h) Population in
Tropical Storm
Population in
Cat. 1 or higher
Countries
Green 1 13 Dec 2020 12:00 102 110 thousand No people Tonga, Niue
Green 2 13 Dec 2020 18:00 102 110 thousand No people Tonga, Niue
Green 3 14 Dec 2020 00:00 111 30 thousand No people Tonga, Niue
Green 4 14 Dec 2020 06:00 111 110 thousand No people Tonga, Niue
Green 5 14 Dec 2020 12:00 111 110 thousand No people Tonga, Niue
Green 6 14 Dec 2020 18:00 102 110 thousand No people Tonga, Niue
Green 7 15 Dec 2020 00:00 102 110 thousand No people Tonga, Niue
Green 8 15 Dec 2020 06:00 83 110 thousand No people Tonga, Niue
Green 9 15 Dec 2020 12:00 102 110 thousand No people Tonga, Niue
Green 10 15 Dec 2020 18:00 102 110 thousand No people Niue, Tonga
Green 11 16 Dec 2020 00:00 102 110 thousand No people Niue, Tonga
Green 12 16 Dec 2020 06:00 102 110 thousand No people Niue, Tonga

Bulletin Timeline

Alert Date (UTC) Category Max winds
(km/h)
Population in
Tropical Storm
Population in
Cat.1 or higher
Location (lat, lon) Countries
GREEN
1 13 Dec 2020 12:00 Tropical storm 65 22000 people no people -17, -173.4 Tonga
GREEN
2 13 Dec 2020 18:00 Tropical storm 65 22000 people no people -17.7, -173.8 Tonga
GREEN
3 14 Dec 2020 00:00 Tropical storm 74 23000 people no people -17.9, -174.1 Tonga
GREEN
4 14 Dec 2020 06:00 Tropical storm 83 100000 people no people -18.3, -174.3 Tonga
GREEN
5 14 Dec 2020 12:00 Tropical storm 83 100000 people no people -18.8, -174.5 Tonga
GREEN
6 14 Dec 2020 18:00 Tropical storm 83 100000 people no people -18.9, -174.2 Tonga
GREEN
7 15 Dec 2020 00:00 Tropical storm 93 100000 people no people -18.8, -174 Niue
GREEN
8 15 Dec 2020 06:00 Tropical storm 83 100000 people no people -19, -173.6 Niue
GREEN
9 15 Dec 2020 12:00 Tropical storm 93 34000 people no people -19.6, -172.4 Niue
GREEN
10 15 Dec 2020 18:00 Tropical storm 102 22000 people no people -20.2, -171.2 Niue
GREEN
11 16 Dec 2020 00:00 Tropical storm 102 1100 people no people -21, -170.2 Niue
GREEN
12 16 Dec 2020 06:00 Tropical storm 102 <1000 people no people -21.8, -168.8 Niue
GREEN
12 16 Dec 2020 18:00 Tropical storm 102 no people no people -25.5, -166.6
Actual track of the current bulletin
The alert for forecast greater than 3 days is limited to Orange level.



Exposed population

Countries

Country
Niue
Tonga

Provinces

Region Province Country Population
Niue Niue 2000 people
Tonga Tonga 98000 people

Populated places

Name Region Province Country City class Population
Alofi Niue Capital <1000 people
Nuku'alofa Tonga Capital 24000 people

Critical infrastructure

Airports, ports, nuclear plants and hydrodams at risk, if affected, are listed below.

Airports

Name IATA Code Elevation (m) Usage Runway type IFR Runway Length (ft)
Niue Hanan IUE 64 Civ. Paved Yes 7600
Haapai HPA 12 Civ. Unpaved Yes 3900
Eua Kaufana EUA unknown 0
Vavau International VAV 72 Civ. Unpaved Yes 5500
Fua'amotu International TBU 38 Civ. Paved Yes 8700

Ports

Name LOCODE Country
Alofi Niue
Pangai TOPAN Tonga
Eua Island Tonga
Neiafu TONEI Tonga
Nuku'alofa TOTBU Tonga

Rainfall

Rainfall accumulation of the past 24h, as detected by the Global Precipitation Measurement mission of NASA. For more information, see https://www.nasa.gov/mission_pages/GPM/main/index.html.

...

StormSurge

0.2 m

The maximum Storm surge height is  0.2m in Neiafu, Tonga. This height is estimated for 15 Dec 2020 01:00 UTC .

The JRC has developed an experimental global storm surge model, which is run after each advisory issued by the regional tropical cyclone centres. The calculations are published about 20 minutes after a new advisory is detected by GDACS. The calculations identify the populated places affected by storm surge up to three days in advance, using the forecasted track. When forecasts change, the associated storm surge changes too and alert levels may go up or down. All links, data, statistics and maps refer to the latest available calculation. If the calculation for the last advisory is not completed, the latest available calculation is shown.

Locations affected by Storm surge (1 locations). Calculation based on advisory number 12 of 16 Dec 2020 06:00:00 UTC. (Simulation using 6 minute resolution)

Alert Date (UTC) Name Country Storm surge height (m)
15 Dec 2020 01:00 Neiafu Tonga  0.2