We're seeing the exact same setup in shares of Dominion Resources (D - Get Report), a diversified utility name with big exposure to generation and transportation assets as well as a retail energy business. Dominion's ascending triangle pattern sports a resistance level at $71. When that $71 level gets taken out, we've got our buy signal, but not before then.
Why all the significance at $71? It all comes down to buyers and sellers. Price patterns are a good quick way to identify what's going on in the price action, but they're not the reason a stock is tradable. Instead, the "why" comes down to basic supply and demand for Dominion's stock.
The $71 resistance level, for instance, is a price where there has been an excess of supply of shares; in other words, it's a place where sellers have previously been more eager to step in and take gains than buyers have been to buy. That's what makes a breakout above $71 so significant -- the move means that buyers are finally strong enough to absorb all of the excess supply above that price level.