Managing frost risk

Page last updated: Thursday, 1 August 2019 - 8:18am

Please note: This content may be out of date and is currently under review.

Frost occurs on clear nights in early spring when the air temperature drops to 2°C or less. Crop damage from frost may occur at any stage of development but is most damaging at or around flowering. Currently growers don't have management or genetic strategies that ensures complete frost tolerance, however there's various risk management options that have been proven to reduce frost risk. This includes; paddock zoning, crop and variety selection, time of sowing, stubble management and managing inputs. This page discusses these options in detail.

Zoning - position in the landscape

The cold air mass that comes with a frost is similar to pouring liquid nitrogen on a flat table - if you tilt the table the liquid nitrogen will slide down the surface. A frost is similar because the cold air will pool in lower areas where the air has nowhere to escape. The identification of frost prone zones will help to inform crop choice and time of sowing. In addition, in the event of a frost, knowledge of susceptible areas will help inform salvage options, for example cutting for hay and grazing. Managing these zones appropriately for the frost risk often enables less frost susceptible enterprise choices to be carried out, such as oaten hay production and livestock grazing.

After a significant frost year, harvest offers the opportunity to map frost affected areas which will help inform management strategies for next season. Research, managed by CSIRO, funded and coordinated by Grains Research and Development Corporation (GRDC) National Frost Initiative (NFI), is currently underway to provide spatial information of frost damage using unmanned aerial vehicles (UAVs). It is hoped that the images gathered from the UAVs will offer early detection of affected areas helping to inform early salvage options. For more information refer to the Ground Cover Issue 121 2016 Frost researchers assess role of drones article.

Climate resources

Frost risk maps are produced July to October each year for growers and advisors to observe the severity and occurrence of frost events for the south west land division. These maps aid in strategic monitoring of crops for frost damage and help inform salvage options.  Historic maps have been compiled for the years 1975 - 2018 showing the occurrence and severity of frost events for each month (July, August, September and October). The August, September and October data has then been combined to show occurrence and severity over these sensitive months in one map. These maps can be viewed below or follow the links on the right panel.

Historic Frost Severity Map - July, August, September, October

Historic Frost Occurrence Map - July, August, September, October

Historic Frost Severity Map - Combined months

Historic Frost Occurrence Map - Combined month

An additional resource is the Seasonal climate information frost risk map. Frost risk maps show the average number of low temperature events occurring in the months when crops are at most risk of frost damage.

The Extreme weather events tool uses data from DPIRD's extensive weather station network to map extreme temperatures, either below or above a specified threshold. It provides real-time information about the location, duration and severity of frost and heat stress events, to help grain growers manage accordingly to reduce their financial impact.

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