Know before you go

• Rainfall
  • Anything over 5 mm/hour or sustained rainfall can rapidly raise river levels.
• Wind
  • Avoid paddling if wind exceeds 55 km/h.
  • Note wind speed is often the presented as the average and does not account for gusts of higher speed. 'windy.com' is great for predicting GUST speed.
• Temperature
  • Cold air adds risk—wear suitable thermal protection.
  • Know you and your paddle buddies. If you don't do well if the cold, maybe pack that extra layer or just sit this one out. Hypothermia is very dangerous and can set in very quickly. 
• River flow
  • Paddle within your ability - a fast river means you must react faster to hazards, features, and move faster into position to take the correct line.
  • It is much safer to paddle the river if the flow is stable or dropping.
    • A rising river brings increased risks like faster flow and lower visibility in the river.
    • These conditions can shift the braids and underlying structure of the river, moving hazards like trees or logs under the surface and make them hard to see. 

In the days before your trip, regularly check several weather sources to build a clear picture of what to expect:

• YR.NO

  • Above the Waimak Catchment - a good indication of forecast rainfall amount and what might be happening on the river in the coming hours/days.

    • Carrington Hut

    • Goat Pass

    • Mount Byrne

  • On the Waimak - know what the wind speed and direction are

    • Mount White Bridge

    • Kinnebrooks Hut

    • Woodstock Downs

• Windy.com 
  • Check the gusting wind speed in the gorge 
    • Waimakariri Gorge wind speed - Windy.Com

• Metservice 

  • Check the weather conditions and temperature at the time of your paddle
    •  Arthur's Pass National Park
    • 3 Day Rain Forecast
    • 5 Day Rain Forecast
    • Canterbury High Country

• Metvuw 

  • Shows precipitation chart for every 6 hours 
    • South Island - 1 Day Forecast
    • South Island - 5 Day Forecast
• Weather Underground 
  • The locals use this one so it much be good! 
    • Arthurs Pass - Weather Underground

Use ECAN’s rainfall data to confirm if rain has already fallen in the headwaters or contributing streams. Remember, anything over 5 mm/hour or sustained rainfall can rapidly raise river levels.

Watch stations like:

• ECAN (Environment Canterbury) Rainfall Data
  • Arthur's Pass - Tributary to Waimakariri upstream of Mt White Bridge ('Put In')
  • Carrington - Tributary to Waimakariri upstream of Mt White Bridge ('Put In')
  • Mount Byrne - Near Harper Pass, Upper end of Thompson River (Tributary of Poulter)
  • Ranger Stream - Next to Poulter River. Downstream of Thompson and Poulter confluence
  • Bull Creek - Cox River where Bull Creek confluences in. Cox River Flows into Poulter 16km upstream of Waimakariri
  • Grasmere - Lake Grasmere. 6km South of the Mt White Bridge 'Put In'. Flows into Cass stream that enters just 300m downstream of 'Put In'
  • Kanuka Hills (Esk River) - Next to the Esk River, 19km upstream of the Waimakariri confluence 
  • Waimakariri Esk - Same location as River Level gauge. Next to Waimakariri River, 2.5km downstream of gorge entrance
  • Cheeseman - At the Ski Field. Covers Craigieburn Range. Flows into Broken River, which flows into Waimakariri 1.5 upstream of the 'Red Iron Bridge'. Or 16km downstream of gorge entrance.

Track actual river height and flow using ECAN gauges. Remember the river flow will lag behind rainfall events - could the river still be rising?

Paddle only when levels are falling and within these safe limits:

• Waimakariri Esk: 2.5km downstream of Gorge Entrance and measures the height of the river. 
  • TopSport recommend this gauge should be a maximum of 0.7m and DROPPING 
  • Lag time: rises 5–10 hrs after rainfall in Arthurs Pass 
• Waimakariri Otarama: 5km upstream of Woodstock and measures the volume of water through the Gorge. 
  • TopSport recommend this gauge should be a maximum of 150 cumecs (m³/s) and DROPPING
  • Lag time: +2–3 hrs after the Esk gauge
• Waimakariri Gorge: located on the Gorge Bridge and measures the height of the river.
  • TopSport recommend this gauge should be a maximum of 1.8m and DROPPING
  • Lag time: +1.5–2.5 hrs after Otarama
• Old Highway Bridge: This gauge is next to the State Highway 1 Bridge and gives the cumecs (m³/s).
  • This is a good indicator of the progress of water down the river
  • Lag time: +7–10 hrs after Gorge rise

Total delay in river rise: about 19–26 hours from rain event in Arthurs Pass to town

Other Notes
Tide info is useful for paddling on the lower Waimak - check the Kaiapoi tide tables.

• Tides chart for Kaiapoi