Volatility is relative. Markets cycle from low volatility to high volatility, a constant ebb and flow. In trading-ranges (consolidations) volatility is low, in a trend it's high. TR's start where trends end, as Pretzel noted, on climactic behavior, so the beginning of a TR has wide swings, high volume, wide price spreads, then at some point in the TR volatility contracts, volume diminishes, spreads and price swings narrow and the market is preparing for the next trend. Price may form an apex ("triangle" for pattern purists) as volatility reaches its nadir, then explodes to a new trend. There may be cycles of high/low vol w/in the TR itself, all preparation for the next move. These are general principles of course and there are infinite variations. Wyckoff is a good source for this, though he doesn't mention volatility specifically, that's what he's talking about.
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