Hurricane Simon made its presence felt across a wide stretch of Mexico's Pacific coastline this week, with Reuters reporting that the storm's sluggish forward speed was a primary driver of the damage it caused. Rather than making a rapid landfall and weakening, Simon crept along the coast, allowing it to unload sustained, heavy rainfall over the same communities for an extended period. Mexican authorities ordered evacuations in multiple states as rivers rose and urban flooding threatened low-lying neighborhoods.
The slow-moving nature of Simon is what separated this storm from a typical Pacific hurricane landfall. When a tropical system stalls or moves at fewer than 5–6 miles per hour, the total rainfall a given location receives can multiply several times over compared to a faster-moving storm of identical intensity — a dynamic that emergency managers call "rainfall accumulation amplification." This is the same mechanism that made Hurricane Harvey so catastrophic when it stalled over Houston in 2017, dropping more than 60 inches of rain in some locations. Simon's behavior along a coastline with steep terrain meant that rainfall runoff was funneled rapidly into river valleys and coastal communities, accelerating flood onset and compressing the time residents had to respond to evacuation orders.
What the broader news coverage tends to underreport in events like this is the distinction between wind-rated preparedness and flood-rated preparedness. Most public hurricane readiness campaigns are built around wind speed categories, but the majority of hurricane fatalities — historically around 90 percent in Atlantic storms, with Pacific patterns similar — are water-related, not wind-related. A household situated well outside a Category 3 wind damage zone can still be in serious jeopardy from a slow-mover's rainfall if it sits in a watershed or near a drainage corridor. Flood insurance penetration in Mexican Pacific coastal states is low, and informal housing construction in arroyos and hillside zones near cities like Manzanillo and Lázaro Cárdenas means that even moderate river rises can be catastrophic. The Reuters report noted evacuations were ordered broadly, though specific displacement numbers were still being compiled as the storm continued its slow transit.
Simon also highlighted a timing pattern worth understanding: October is historically the peak of the Eastern Pacific hurricane season's late-season activity, and storms forming or persisting into October tend to encounter cooler sea surface temperatures that reduce their peak intensity but do not necessarily reduce their moisture content or stall risk. A weakening storm is not a passing storm, and Simon's behavior illustrated that clearly.
