If you have plans in the mountains, on the Caribbean coast or along the Pacific this weekend, build in some flexibility. Rain is coming, and the ground in much of Costa Rica is already soaked. The Comisión Nacional de Emergencias declared a green alert today for a large part of Costa Rica ahead of Tropical Wave 40, which is expected to move over the country across the weekend.
The alert covers the Caribbean region, the Northern Zone, the South Pacific, the Central Pacific and the canton of Turrialba. Green is the lowest of Costa Rica’s three alert levels. It does not mean evacuations or closures. It means conditions are expected to deteriorate enough that you should be paying attention, and that local emergency committees have been told to start watching their high-risk areas.
The reason the alert matters more than the level suggests is the state of the ground. Weeks of rain have left soils saturated across much of the affected territory, and saturated soil cannot absorb any more water. When the next storm arrives, that water runs off instead, which is how rivers rise quickly and how hillsides give way.
That is why the emergency commission singled out national parks and mountain routes in its guidance. Steep, wet terrain is where the risk shows up first, and it shows up fast. A trail that was fine on Friday can be a different proposition after a heavy Sunday afternoon downpour.
Saturday was the quiet half of the weekend. The Instituto Meteorológico Nacional expected clear or lightly clouded conditions over the Pacific slope and the Central Valley through the morning, with variable rain in the Caribbean and Northern Zone, and isolated afternoon downpours with thunderstorms in the southern Nicoya peninsula and the Central and South Pacific.
Highs were forecast near 27.8°C (82°F) in San José, 32°C (90°F) in Golfito and 30.5°C (87°F) in Limón. The heavier weather is expected to build from Sunday into early next week. If you are deciding when to do the drive or the hike, earlier is better than later.
For anyone driving, the hazard is not only water on the road. Rain brings fog to the mountain sections, which cuts your visibility at exactly the point where the corners tighten, and it brings down branches and loose material onto the carriageway. Slow down before the weather forces you to and leave more space than feels necessary.
Route 32, the main link between San José and Limón, is worth a check before you set out. The Zurquà sector through Braulio Carrillo National Park closes regularly after heavy rain when mud and rock come down onto the road, and closures there can last hours with no reopening time announced. Road status is published by the transport ministry on its social channels rather than a website.
Two volcanoes are also under green alerts that were already in place before this weekend. You can still visit Volcán Poás, but the crater viewpoint is now capped at 56 people, and you’ll need a helmet on the main trail. Both measures assume the same thing — that if the volcano throws material, you want fewer people at the rim and something between that material and their heads.
Rincón de la Vieja has recorded more than 100 eruptions since July, and the concern there is lahars, the fast-moving slurries of water and volcanic debris that travel down river channels. Authorities have posted signage along the Pénjamo, Azul and Pizote rivers and the Quebrada Azufrada, and have asked people to stay out of any river carrying volcanic material and to keep animals from drinking it. That water can be hot and acidic, and a lahar arrives with almost no warning.
The emergency commission also asked people to rely only on official sources during the alert, which seems like a reasonable request in a week when soils are saturated and rumors travel faster than confirmed information. Conditions can change through the day, and a forecast issued the previous evening will not always match what arrives.
