By RIO YAMAT (The Associated Press) LAS VEGAS (AP) — Scorching heat across the U.S. already has caused more than a dozen deaths in Texas alone and led to mounting misery for millions of people from the Pacific Northwest to the South. And the official end of summer is still months away. Here’s a guide on how to keep cool and stay safe in the punishing temperatures as the latest heat wave ravaging the country spreads east. Heat kills more Americans than any other weather event, including tornadoes and flooding, even though most heat-related deaths are preventable through outreach and intervention, according to the Environmental Protection Agency. “Heat is the silent killer.