About our snow storage calculations

During spring and summer, snow in the Waitaki catchment melts, flowing into rivers and lakes and contributing to hydro inflows and storage. Snow melt is estimated to contribute approximately half of the inflows to the Waitaki catchment over the summer period although this figure varies1.

Meridian collects information on the amount of water stored as snow so we can estimate its impact on inflows.

Meridian makes no representation as to the amount, timing and location of any such inflows through the publication of this information.

Calculating snow water equivalent (SWE) is complex and resulting estimates (and their relationship to lake inflows) have a high degree of uncertainty. Reliance should not be placed on the accuracy or completeness of the estimates provided and you should not use this information for investment or trading purposes. Meridian publishes a monthly operating report on the NZX and ASX outlining the current hydro storage position each month.

Seasonal snow storage in Waitaki catchment as at 22 October 2018

Snow graph 22 October 2018

Snow storage relative to the time of year
Current 1481 GWh
Mean 1519 GWh
Percentage 97%
Minimum 861 GWh
Maximum 2343 GWh

This chart is updated fortnightly. The chart shows the current amount of snow stored in the Waitaki catchment relative to the long term distribution. The black line shows current snow storage. The coloured areas show the long term variability (mean, min, max, 25th%ile and 75th%iles). 

1. McKerchar, A. I., C. P. Pearson, and B. B. Fitzharris. 1998. Dependency of Summer Lake Inflows and Precipitation on Spring SOI. Journal of Hydrology 205:66-80.