The airport remains fully operational, but several flights were delayed Wednesday morning.
Authorities noted illegal visits can put rescue teams' lives in danger.
Volcán Turrialba in all its glory, thanks to Cusuko Fotografía.
Volcanologists said the formation of a lava lake is obvious proof of the rise of magma to the surface.
Vulcanologists conducted an inspection of Poás and found rocks of various diameters ranging from 40 centimeters to 2 meters (1.3-6.5 ft) that had been hurled as far as one kilometer through the air.
A National Seismological Network's report noted that low-intensity volcanic tremors are following ash explosions at Turrialba Volcano.
Weather conditions have prevented OVSICORI staff from approaching or conducting flyovers with a drone over the crater to measure the depth of the magma body.
Turrialba Volcano increased its activity once more over the weekend with vapor, gas and ash explosions, volcanologists reported.