Cloud seeding program

Hydro Tasmania no longer conducts a cloud seeding program. Cloud seeding flights stopped in June 2016.

Hydro Tasmania sometimes used cloud seeding over some catchments to produce a moderate increase in rainfall. When operating, the program was reviewed by independent experts and we sought to keep Tasmanians informed about it.

What is cloud seeding?

Cloud seeding is a technique that increases rainfall in a target area. Cloud seeding in the right conditions can increase the amount of rain that falls over targeted catchments. Cloud seeding only occurs when the Bureau of Meteorology forecasts rain, and even then only if conditions are favourable for cloud seeding to be successful.

Hydro Tasmania was involved in both experimental and operational cloud seeding over Tasmania and mainland Australia from 1964. In that time we developed a great deal of knowledge and expertise in the area.

Our cloud seeding operations were usually conducted between May and October each year when conditions were suitable.

Further information can be found below.

Environmental tests

In April and November 2014 soil samples were collected at two different locations in each of the townships of Queenstown, Rosebery and Zeehan.

Water samples were also collected from water bodies or creeks in or near these townships.

The samples were tested for acetone and dichlorobenzene as these two chemicals make up more than 95% of the cloud seeding solution. Neither chemical was detected in any of the samples. The test results can be viewed .

In a typical year the amount of silver iodide released as a result of cloud seeding is less than half of one teaspoon per square kilometre.


West coast study

A study of the socio-economic impacts of cloud seeding on the West Coast of Tasmania was completed during 2006/07 by Hydro Tasmania and the West Coast Council. It followed repeated criticism from the West Coast Council which represents residents and businesses who have expressed concerns about adverse impacts of cloud seeding-induced rainfall in the municipality.

Hydro Tasmania has suspended its cloud seeding program over the King catchment since 2008. We worked with the West Coast Council to improve communications and address community concerns over the cloud seeding program. Both parties acknowledge the differences of opinion that remain about the variability of weather patterns and the amount of scientific debate on cloud seeding.

The full program of Hydro Tasmania's response to report can be found in the media release.

The report was prepared by SGS Economics and Planning:

Overview: Socio-economic impacts of cloud seeding on the West Coast

Report 1: Effects of cloud seeding on the rainfall on the West Coast

Report 4: Economic impacts of cloud seeding

Annual summaries

During the 2016 season a total of 31 operational flights were undertaken by Hydro Tasmania, with conditions suitable for seeding on 12 occasions. Multiple catchments were targeted on some cloud seeding flights.

View the cloud seeding summary for 2016

View the cloud seeding summary for 2015

View the cloud seeding summary for 2014

View the cloud seeding summary for 2013


Historical flight maps

After each cloud seeding flight we post the flight map on our website.

Reading the map

Blue lines indicate the flight path of the cloud seeding aircraft when not seeding. The red lines mark the cloud seeding flight path.

The seeding track is located 1/2 hour upwind from the target area and depends on wind direction and wind speed at seeding altitude on the day.

Flights maps for previous years back to 2013 can be found via the links below.