Poás Volcano – Our Restless Sentinel

Poás Volcano is one of Costa Rica’s most famous tourist attractions. Its crater ranks amongst the world’s largest and is known for its stunning, emerald-colored, bubbling sulfuric lake. The Poás Volcano National Park is a must-visit destination, offering breathtaking views, unique geological features and many options.

…and 2025 is the year of Poás – the volcano has been experiencing unrest and has undergone a series of eruptions – and it seems like it is not yet finished! As of writing, the Costa Rican National Emergency Commission (CNE) has issued a RED ALERT for the Poás Volcano National Park area following the explosive April 23 eruptions which saw gas & ash violently eject from the crater to reach an altitude of 4,500 meters or nearly 15,000 feet. Newsfeeds, both local and international, are sharing developments of the awakened mountain. This article will not be updated following publication – please monitor developments via official government channels such as CNE.

Located only 30km from downtown San Jose and even closer to the country’s major airport, the volcano is an ever-present threat to the capital city and over 3 million residents – or nearly 60% of Costa Rica’s total population – who live in the Greater San Jose Area. And it is only one of SEVERAL active or dormant volcanoes that surround San Jose, some standing much closer to the city than Poás.

THE 2025 UNREST

Since the start of 2025, the volcano has been exhibiting elevated unrest which includes gas & ash eruptions, earthquakes and steam explosions which have launched rocks and material in all directions. In early March the crater emitted a plume of material which reached an altitude of 400 meters above the rim – the alert level was increased and the National Park was closed to the public. The National Park reopened, in a limited capacity, on March 11 – only 56 visitors at a time were allowed to access the Park. Hiking trails were closed, access time limited and all crater rim visitors were issued helmets.

The elevated activity continued with March 18th being especially active – in a 24 hour span, over 200 earthquakes were recorded and nearly 700 tons of sulfur dioxide were emitted from the crater. The crater lake, Lagunas Caliente, started to disappear. On March 28 a series of eruptions ejected rocks to a distance of 150 meters and expulsed gas & ash 200 meters into the air. The National Park was again closed and remains so at the time of writing.

April 21 and 23 saw the most violent activity, with ash clouds reaching an altitude of 4,500 meters. A Red Alert was issued and nearby town & villages were put on notice. And this is where we are today, on April 27. The future is uncertain and we have no idea when Poás Volcano National Park will re-open.

OUR RESTLESS VOLCANOES

Definitions vary, but Costa Rica has nine ‘active’ volcanoes – meaning they are either erupting or showing unrest. These include Poás, Irazú, Rincón de la Vieja, and Turrialba. A few volcanoes are considered ‘dormant’ meaning they are not erupting or showing unrest but they erupted in recent geological times and have the potential to erupt in the future – these include Arenal, Barva, Miravalles, and Tenorio volcanoes. ‘Extinct’ volcanoes like Tortuguero, Pelado, Chopo or Tilarán will never erupt again as they have lost their hot magma reservoirs, however many still retain heat and are surrounded by hot springs and, sometimes, fumaroles. For a tiny country, that is quite the collection!

THE BEAUTY OF POÁS VOLCANO NATIONAL PARK

There is a reason for why Poás is one of the gems in the crown of Costa Rican tourism – the sheer beauty of the volcano, crater, surrounding trails, crater lakes, and expansive views is unmissable. At nearly 2,700 meters, or 8,900 feet, in elevation the cool & refreshing mountain air is a treasure and a welcome respite form the tropical humidity that lingers just below the mountain.

Laguna Botos is a shallow lake that fills an extinct crater. This almost perfectly circular mountain lake is 370 meters across, up to 9 meters deep and almost 8,000 years old – dating back to the last eruption of this now dormant (but not extinct) crater. Laguna Botos is likely fed by precipitation, groundwater, and potentially hydrothermal fluids within the crater – with the waters draining into Río Ángel. Pristine cloud forests surround the lake an every side, complimenting the lake’s cool green waters.

The slopes of the mountain (away from the crater areas where heat and acidic vapors suffocate plant life) are covered with lush Montane & Cloud Forests. The volcanic soil is super-rich and promotes the growth of abundant plant life while the high elevation ensures the nearly constant mists refresh and envelop this very unique Montane biome. Several trails wind their way through the forests.

The Poás crater is nothing short of spectacular – 1320 m (4330 feet) wide (that’s nearly 1 mile) and 320 m (1050 feet) deep, the crater is rough, steaming, and painted with multi-colored bands – white, black, gray, brown, yellow and rusty red rocks attest to the primeval nature of this location. Green ridges surround the crater, at times disappearing behind the billowing clouds of steam. Wafts of sulfuric air drift along the wind.

And the star of the show – the often-emerald crater lake called Laguna Caliente – is a temperamental creature, changing colors, temperature, pH, and at times growing or disappearing from view. This is the most acidic lake in the world with a pH level that sometimes falls to ‘zero’ – comparable to battery acid. The lake’s bottom is covered with a layer of liquid sulfur!  The temperature ranges from a pleasant coolness to a hot & boiling hellscape. Lagunas Caliente is about 300 meters across and 30 meters deep, although the size and depth of the lake varies. A true gateway to Hell, but dressed up for Instagram fame!

The Poás Volcano National Park includes a number of trails, some short and some many miles in length. The trails meander through the volcanic landscape and explore the crater, Cloud Forests, lakes and formations that dot the National Park.

ACCESS, PARKING & TRAILS

Tickets need to be purchased in advance from the SINAC (Sistema Nacional de Áreas de Conservación) website – you will need to provide some information and choose the day and time of your visit. Visitors not in possession of a pre-purchased ticket will not be allowed to enter the Park. Current Park information can be found on the SINAC website linked above – although it seems that the website is not updated with urgency so seek several sources for confirmation of important information like Park closures. Also book tickets a few days in advance as the SINAC website is known to frequently fall off-line (it seems to be off-line at the time of writing). In summary (this info is current as at 27 April 2025 and will not be updated):

• For foreigners, entrance costs are $5 (children 2-12) and $15 (visitors 13 years old +)
• Local Costa Ricans pay 500 Colones ($1) and 1000 Colones ($2) respectively
• Parking fees are 1000 Colones ($2) for motorcycles 2000 Colones ($4) for light vehicles
• The carpark is a short walk from the crater – 600 meters or 2000 feet. It is a prepared & wide path that is wheelchair accessible
• The Botos Lagoon Circuit is 3.4 km or 2.1 miles long, taking views of the main crater, the Botos Lagoon, lush vegetation and landscape panoramas. It is a part of the main access trail between the carpark and the main crater
• Use Waze or other map app to get directions to the National Park. There is also bus access from Alajuela – but only on Saturdays, Sundays and Holidays
• The Poás Volcano National Park is currently CLOSED indefinitely due to ongoing volcanic unrest. 

ERUPTION EFFECT ON TOURISM & LOCAL COMMUNITIES

The 2017 eruptions have had a long & devastating impact on tourism and surrounding communities – unfortunately it looks like this year’s volcanic unrest has the potential to be equally destructive.

On April 9, 2017, National Park officials placed restrictions on Poás visits due to increased emissions of toxic gases at the summit crater. An explosion on April 12 caused the decision to close the park for visitors, with  2.5 km safety zone secured around the crater.  Some nearby residents were also evacuated because of the activity. On April 14, 2017, two eruptions created an over three kilometer ash and vapor column. Further explosions occurred after 2 days, on April 16. At that time, Lagunas Caliente disappeared and earthquakes shook the mountain and surrounding areas.

A large blast on April 22 sent red-hot rocks spilling out of the crater to damage buildings and infrastructure. Costa Rica President Luis Guillermo Solis toured the surrounding towns to show support for the populace. Business owners described the negative financial impacts the volcano park closure were causing, and Solis released a video in Spanish and English urging potential tourists to visit the nearby community shops and restaurants.

The emergency continued well into 2018 as rockfall, landslides, earthquakes, ashfall, and projectile rock ejections continued to threated local communities and damage the infrastructure.  The National Park re-opened in September, nearly 18 months following the April 2017 eruptions. Nearby communities suffered immensely – not only due to damaged infrastructure – such as water pipes, concrete foundations and fencing –  but also due to the near erasure of tourism in the area. Accommodation providers, tour operators, restaurants, cafes, pubs, tourist shops and many other businesses that rely on tourist dollars were effectively shuttered.

SIGNIFICANT HISTORICAL ACTIVITY

• Poás has erupted 40 times since 1828.
• 2024-2025: Heightened volcanic activity since late 2024, including the most recent eruptions on April 21-23, 2025, has led to closures and potential economic impacts on tourism.
• A 2017 eruption caused the park to be closed for about 18 months, leading to economic losses for local businesses.
• In January 2009 Poás was near the epicenter of a 6.1-magnitude earthquake that killed at least forty people and affected the Central valley area including San Jose.
• On May 17, 1953, an eruption occurred that started a cycle and lasted until 1956.
• Between 8 October 1914 to 15 May 1915, a significant eruptions produced extensive and far-reaching ashfalls.
• A 1910 eruption was a significant event characterized by a large mushroom-shaped cloud of ash and steam reaching heights of 8 km above the summit.

COSTA RICA’S VOLCANO ALERT LEVELS & RESOURCES

Red Alert: This is the highest level, indicating a major volcanic eruption and the highest risk to people and property. The Poás Volcano National Park is under a Red Alert as at 27 April 2025.
Orange Alert: This alert level indicates a moderate to high risk due to ashfall and gas exposure, typically affecting areas near the volcano.
Yellow Alert: This level signals increased caution and vigilance, with areas under yellow alert experiencing intermittent ashfall and volatile gas concentrations.
Green Alert: This is a precautionary warning indicating that heightened volcanic activity is being closely observed, but not necessarily an immediate threat.

A few official resources, presented below, can be consulted to learn about the alert levels and verify volcano and surrounding area alert level status. Please note that these, although official, can experience delays with presenting up-to-date information:

• Costa Rican National Emergency Commission (most up-to-date resource) CNE

• Volcanological and Seismological Observatory of Costa Rica (provides delayed notifications) OVSICORI
• National System of Conservation Areas (very slow to update) SINAC

A MUST-SEE ATTRACTION (WHEN AVAILABLE)…

It’s not only about the steaming crater – Lagunas Caliente & Botos are themselves seen as major attractions worthy of their own Wikipedia pages. The cool & misty Cloud Forests and the spectacular high elevation views over the surrounding landscape are icing on the cake. All of these sights & experiences are wrapped in one neat little package just a short day-trip away from San Jose.

Imagine living in a place where majestic, towering volcanos add a touch of surrealism to the lush, jungle surrounds. With their cloud-forest slopes, stunning crater lakes, panoramic vistas and hellish craters, the volcanoes are definitely worth a visit! This can be your life, and we can turn your dreams into reality much faster and easier than you think! To browse properties available in the South Pacific area of Costa Rica, see the RE/MAX WE SELL PARADISE  listings here.

cover image c/o Mariordo, wikicommons.