Winter Backcountry: Crampons, Avalanche Risk, Route Finding

Winter changes everything in the New Zealand backcountry. The same valley you trotted through in February is now a different mountain — frozen tussock, hidden creeks, avalanche paths that did not exist in summer. We are not here to scare you off winter tramping. We do it most weekends. But the gap between summer competence and winter competence is wider than people think.

The mindset shift#

In summer, an unplanned bivvy is uncomfortable. In winter, it can kill you. That single fact should reshape every decision: gear, pace, turnaround time, partner choice. If you would walk into a route in summer with "she'll be right" energy, you are not ready for that route in winter. Plan harder. Bail earlier.

Crampons and ice axe — the non-negotiable kit#

For tops above ~1200 m between June and October on the South Island, you need both crampons and an ice axe, and you need to know how to use them.

• Crampons: Aluminium for soft-snow approaches, steel for refrozen névé and ice. A 10-point semi-rigid is the sweet spot for most NZ tramping. Make sure they fit your boots before the trip, not at the trailhead.
• Ice axe: 60-70 cm walking axe is fine for most ridges. Practise self-arrest on a safe slope with a runout before you ever need it for real. A self-arrest you have only read about is not a self-arrest.
• Helmet: If there is any chance of climbing or rockfall above you, bring it. They weigh 300 g.

The NZ Mountain Safety Council runs avalanche and alpine skills courses every winter. NZ$300-500 for a weekend that genuinely changes how you move on snow. Cheaper than a helicopter rescue.

Reading avalanche risk#

Check the NZ Avalanche Advisory (avalanche.net.nz) every morning of a winter trip, ideally for several days before you start. Read the bulletin, not just the colour code. The text tells you which aspects, which elevations, and which weak layers matter today.

Key terrain features to identify and avoid in elevated risk:

1. Slopes between 30 and 45 degrees — the most common avalanche angle.
2. Lee aspects after recent wind — wind-loaded snow is the classic trigger zone.
3. Convex rolls and gully systems — terrain traps that concentrate debris.
4. Anywhere with a recent crown line, even from days ago.

Key tip: If your morning bulletin says "Considerable" or worse on the aspects you are about to climb, change the plan. There is always another route, another weekend, another season. The mountain does not negotiate.

Route finding when the trail disappears#

Summer trails are marked by orange triangles and worn ground. In winter both can vanish under a metre of snow. Things that help:

• Pre-load the route on your phone in a GPS app that works offline (we obviously like ours, but Topo50 + GPX is the universal answer). Battery dies fast in cold, so carry a power bank in an inside pocket where it stays warm.
• Identify handrails before you leave: a creek, a ridge, a treeline. Even in whiteout you can usually navigate to a linear feature.
• Set a bingo line — a time or weather threshold that, if crossed, means you turn around no matter how close the summit looks.

Layering for the conditions you will actually meet#

The classic NZ winter tramping mistake is dressing for the carpark. You sweat out on the climb, then freeze when you stop on the tops. Three rules that fix it:

• Start cold. If you are warm at the trailhead you are overdressed.
• Carry a real belay jacket — synthetic insulation, big enough to fit over everything else. Pull it on the moment you stop.
• Mid-layer should be wool or synthetic, never cotton. A wet cotton t-shirt under your shell is genuinely dangerous.

When to call it#

Three rules we apply to every winter trip:

1. If two of your party are getting cold faster than the rest, the whole party turns around.
2. If visibility drops below 50 m and you cannot navigate by handrail, you stop and shelter.
3. If you are not at the saddle by the agreed time, you do not push for it. Daylight in winter is a hard limit.

Winter is the best time of year on a New Zealand mountain. It is also the least forgiving. Build the skills before you need them, carry the kit before you need it, and turn around earlier than feels heroic.