2 days spent touring across the Spearhead Traverse with my dad.

Weather Conditions:
Sunshine with few clouds.
Temps: -2 to -4 in shade. Spring oven in the sun.
Freezing Level to 1900m observed on March 29th.
Calm with some light winds from the NE on March 28th.
Winds on March 29th were strong to extreme from various directions (mostly NE) in specific spots. Otherwise calm or light.

Snow Conditions:
5-10cm of new snow from March 27th redistributed by NE winds.
Breakable to supportive suncrust on most solar aspects.
Polar aspects skiing well with boot-top spring powder.
Mid and lower pack well consolidated.

Avalanche conditions:
Old cornice releases evident off Decker.
New cornice releases (March 29th) on Overlord Peak to size 2-2.5 (see photo).
Solar affect with daytime warming (more pronounced March 29th) causing loose wet avalanche size 1-2.

One skier accidental size 1.5 windslab in the notch descending onto the Overlord Glacier (see report below and photos)
Slab dimensions: 10m wide by 5 meters long. Crown 10-80cm.
Ran ~75m. Involvement, no burial or injury.

Other than isolated windslabs, no other avalanche concerns.

Report:
Fantastic conditions for the Spearhead Traverse with my dad. Great skiing, great views and comfortable temperatures.

Notches descending from Decker, Naden Glacier, Iago Glacier and the traverse between MacBeth Glacier and Iago Glacier continue to be the cruxes of the traverse. Icy frozen tracks and suncrust make them unpleasant. Singing pass conditions undetermined, we finished over Flute to ski down the 'on-piste'. We spent the night camped down below the MacBeth glacier. Great spot with awesome sunset views.

Winds up high on March 29th were interested and isolated to certain areas on the route where intensive blowing snow could be seen. Wedge, Overlord, Fitzimmons, Castle Towers and Flute were all seen or experienced to be very windy. Wind speeds were irregular ranging from moderate to extreme.

In the morning, a solo traveller gained us and asked to follow along with my dad and myself. We were happy to have more company along and even happier to keep an eye out for the lone wanderer on the second half of the traverse.
Our crux on day two came from descending through the notch below Overlord Peak to descend onto the Overlord Glacier. ( 50° 0'59.19"N 122°49'18.30"W). Though another group had passed through one hour previously, tracks were non-existant or raised within the sastrugi. The wind was raking the snow making it hard to communicate and uncomfortable to sit still. I had concerns with recent wind loading as it had been visibly intense in the past hour and a half. With my dad waiting behind me, I bootpacked to safe rock to view the slope and cornices on the East to West ridge of Overlord. 2 fresh cornice releases had plowed over old ski tracks traversing underneath them, we would be giving all other cornices a very wide berth. The notch looked fatter than I'm used to, that said I hadn't been there in a year. Feeling the edge of the wind-loaded pillow with my pole handle, there seemed to be 15cm of freshly loaded snow on top of firm snow on the edge. My bigger concern, other than cornices lower down, was a loaded pillow above the notch slope (in red on annotated photo) that I really didn't want to toe trigger. Thinking we could skirt around the majority of the slab, I instructed the others. to follow in my tracks and started down sidestepping on the shallow edge of the pillow, stomping the freshly loaded snow away. Once low enough, a quick jump turn put me under the rocks and out from the pillow. As I continued down following under the rocks and avoiding the pillow, I see 10cm deep slab release a foot below my ski tips. Noticing motion in my peripheral, I yelled "Avalanche!" only to see my dad riding down in the debris before quickly stopping next to me, 5 meters below where he triggered it. He had lost no skis or gear and suffered no injuries; just a little snow in his jacket.
So what happened? I had greatly underestimated the amount of loading that had occurred since the other group passed through and in following in my tracks, my dad triggered the windslab. He's got a bit more beer belly I guess. What I had felt with my pole of only 15cm of wind-loaded snow on a firm surface was likely the loading in the past 15 minutes on top of the real slab! The avalanche was not super small nor large enough to cause harm in most terrain. Given the nature of the slope, much of the debris stopped mid-slope. Burial would have been unlikely. That said, I prefer my friends, peers, guests and especially family, have no avalanche involvement ever. Although in a recreational mindset skiing with my dad, I had a lot of red flags going off and trying to save time and energy by taking the more efficient route turned out to be too risky.
Additionally, it shows how conditions can change fast and even though groups are regularly doing the traverse in good weather this time of year, there is still hazards in the mountains. Hopefully these risks are well considered when travelling solo like our pal.

Moral: carry explosives... But actually, when red flags are speaking to you, don't let objectives and apprehension of the long way round (see photo) get in the way of good decision making and safe mountain travel.

All in all, a good learning experience without consequences that I've had the opportunity to learn from. I hope other people can also learn from these experiences.

All said, great conditions in the mountains. Keep those senses alert and both hands on the steering wheel!

Enjoy the spring skiing!