kootenay vignette: drop Peace vignette cross-references

Tighten narrative to what's happening in the Kootenay Lake Region
itself. Remove explicit comparisons to the FWCP Peace vignette in
the recent-decade table, snowpack headline, ASWS QA cross-check,
snowpack interpretation, precipitation interpretation, snow
interpretation, and salmonid-habitat closer. Also trim the
Cordillera-wide background paragraph from a four-basin list to the
Columbia-basin attribution that's load-bearing for the Kootenays.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: NewGraphEnvironment

vignettes/kootenay-lake.Rmd

@@ -280,11 +280,10 @@ The recent decade was 1.6 to 1.8 °C warmer than the pre-warming
 reference for annual mean, daytime maximum, and overnight minimum,
 with both window and trend p-values below 0.001. Vapour pressure
 deficit is up significantly on both tests. Annual precipitation
-was about 6 to 7 % *lower* in the recent decade — and unlike the
-FWCP Peace just to the north, the long-term Mann-Kendall trend
-test does confirm a steady year-on-year decline (trend p ≈ 0.02).
-Soil moisture is roughly flat. Relative humidity shows a small
-significant decline.
+was about 6 to 7 % *lower* in the recent decade, and the long-term
+Mann-Kendall trend test confirms a steady year-on-year decline
+(trend p ≈ 0.02). Soil moisture is roughly flat. Relative humidity
+shows a small significant decline.
 
 ```{r compare-recipe, eval = FALSE}
 cmp <- cd::cd_compare(ts)   # defaults: 2015–2025 vs 1951–1980, Welch t-test
@@ -407,27 +406,19 @@ sets the timing of the spring freshet — the annual flood pulse that
 shapes channel morphology, mobilizes spawning gravels, and refills
 off-channel rearing habitat for resident salmonids. Cordillera-wide,
 snowpack has been declining for decades [@mote_etal2018Dramaticdeclines;
-@pederson_etal2011UnusualNature]. For four BC river basins (Fraser,
-Peace, Columbia, Campbell), Najafi et al. [-@najafi_etal2017AttributionObserved]
-attribute observed spring SWE decline to anthropogenic forcing —
-including the Columbia basin, the parent system of the Kootenays.
-For the neighbouring Fraser, Kang et al.
-[-@kang_etal2016ImpactsRapidly] document a ~10-day advance of the
-spring freshet over 1949-2006.
-
-**For the Kootenay Lake Region the snowpack signal is sharper than
-in northern BC reporting regions, in line with the Selkirks /
-Purcells sitting at warmer latitudes than Peace-region snow zones.**
+@pederson_etal2011UnusualNature]. Najafi et al. [-@najafi_etal2017AttributionObserved] attribute
+observed spring SWE decline in the Columbia basin — the parent
+system of the Kootenays — to anthropogenic forcing.
+
+**The Kootenay Lake Region snowpack signal is sharp.**
 Annual snow water equivalent (SWE) is down **23%** (206 → 160 mm)
 since the 1951–1980 reference. Annual snowfall and annual snowmelt
 both fell about 15%, and the **snowmelt midpoint (DOY-50) shifted
 12.6 days earlier** in the year. Annual peak SWE — the seasonal
-maximum — dropped **92 mm** (-16%). And — distinct from the FWCP
-Peace where total precipitation is roughly stable — **annual
-precipitation in the Kootenay Lake Region has declined ~7%** since
-the reference period, with a long-term Mann-Kendall p of 0.02.
-Together this is a "warmer *and* drier" story rather than a
-"warmer-only" one.
+maximum — dropped **92 mm** (-16%). **Annual precipitation in the
+Kootenay Lake Region has declined ~7%** since the reference period,
+with a long-term Mann-Kendall p of 0.02. Together this is a
+"warmer *and* drier" story rather than a "warmer-only" one.
 
 A few notes on how to read the snow numbers below.
 
@@ -447,10 +438,9 @@ simplified snow layer in the underlying atmospheric model).
 Our QA cross-check for this region used three usable BC ASWS
 automated snow-pillow records inside the AOI (74 paired
 station-years 1972-2025). Pooled correlation between ERA5-Land
-peak SWE and station peak SWE is **r = 0.90** — meaningfully
-better than the FWCP Peace's 0.51, meaning the model tracks
-year-to-year variability well at these high-elevation Kootenay
-sites. But the absolute bias is large and uniformly negative:
+peak SWE and station peak SWE is **r = 0.90**, meaning the model
+tracks year-to-year variability well at these high-elevation
+Kootenay sites. But the absolute bias is large and uniformly negative:
 ERA5-Land is **40-63% too low** at Moyie Mountain (1835 m,
 Purcells alpine) and Redfish Creek (2100 m, Selkirks alpine),
 consistent with both stations sitting at high-snow microsites
@@ -585,12 +575,10 @@ cd::cd_plot_timeseries(ano, variable = "snowfall_fraction", period = "annual",
 Three findings carry the snowpack story for the Kootenay Lake Region.
 
 **Snow is leaving *and* falling less.** Annual snowfall is down 15%
-(649 → 554 mm) — distinct from the FWCP Peace pattern just north,
-where the snowpack decline was almost entirely about earlier melt
-on roughly stable annual snowfall. The Kootenay Lake region is
-warm enough at the relevant elevations that the snow-vs-rain
-threshold is being crossed in the calendar — winter precipitation is
-falling more often as rain instead of snow. This matches the
+(649 → 554 mm). The Kootenay Lake region is warm enough at the
+relevant elevations that the snow-vs-rain threshold is being crossed
+in the calendar — winter precipitation is falling more often as rain
+instead of snow. This matches the
 threshold finding from Knowles et al.
 [-@knowles_etal2006TrendsSnowfall]: the strongest snowfall-fraction
 declines in the western US occur where winter wet-day minimum
@@ -1039,12 +1027,8 @@ mean temperatures all tell the same story. The whole region moved
 together — there is no warming hot-spot at the ecoregion scale.
 
 **Precipitation is declining and the decline is regionally
-consistent.** This is the place where the Kootenay Lake Region
-diverges sharpest from the FWCP Peace just north. The Peace
-showed mostly-flat annual precipitation with significant
-*increases* in two of its five ecoregions; the Kootenays show a
-**~7% decline** in annual precipitation from the 1951-1980
-reference to the 2015-2025 recent decade, with a long-term
+consistent.** Annual precipitation dropped **~7%** from the
+1951-1980 reference to the 2015-2025 recent decade, with a long-term
 Mann-Kendall p of 0.02. Spatially the decline is consistent across
 all four ecoregions of the AOI, so the pattern at the regional
 average mirrors what each watershed group sees individually. All
@@ -1068,13 +1052,10 @@ keeps the topsoil layer roughly even, but the resulting
 late-summer water deficit shows up in stream baseflow rather than
 in soil-moisture statistics.
 
-**Snow is leaving *and* falling less.** This is the second place
-the Kootenays diverge from the FWCP Peace pattern. The Peace's
-snowpack decline was almost entirely about earlier melt on
-roughly stable annual snowfall. The Kootenays show **annual
-snowfall down 15%** alongside the freshet shift — winter
-precipitation is falling more often as rain instead of snow,
-matching the threshold finding from Knowles et al.
+**Snow is leaving *and* falling less.** Annual snowfall is
+**down 15%** alongside the freshet shift — winter precipitation is
+falling more often as rain instead of snow, matching the threshold
+finding from Knowles et al.
 [-@knowles_etal2006TrendsSnowfall] for sites with winter wet-day
 minimum temperatures warmer than -5 °C. Annual snow water
 equivalent (SWE) is down 23% (206 → 160 mm); summer SWE has
@@ -1097,19 +1078,13 @@ lose substantially more thermal habitat than warm-water species
 under the same forcing. Both findings carry directly into the BC
 interior cold-water cohort the Kootenay Lake Region supports. The evapotranspiration
 imbalance means low-flow conditions in late summer are not being
-relieved (precipitation is falling, not rising as in the Peace);
-the cold-water input that high-elevation snowpack provides to
-streams during the warmest, most thermally stressful weeks of
-summer is dropping in parallel with summer SWE; and the spring
-freshet — the dominant high-flow event that shapes channel
-morphology, mobilizes spawning gravels, and refills off-channel
-rearing habitat — is shifting weeks earlier. The neighbouring
-Fraser Basin shows the same shift —
-@kang_etal2016ImpactsRapidly documented a ~10-day advance in the
-spring freshet at Hope between 1949 and 2006, with persistent
-declines through autumn recession just when salmon are migrating
-up the Fraser. Lower
-Columbia River reaches below Hugh Keenleyside Dam are
+relieved by precipitation; the cold-water input that high-elevation
+snowpack provides to streams during the warmest, most thermally
+stressful weeks of summer is dropping in parallel with summer SWE;
+and the spring freshet — the dominant high-flow event that shapes
+channel morphology, mobilizes spawning gravels, and refills
+off-channel rearing habitat — is shifting weeks earlier.
+Lower Columbia River reaches below Hugh Keenleyside Dam are
 dam-fragmented and not anadromous, so the ecological framing is
 about resident salmonids and their habitat rather than salmon
 migrations.