The speed of the eruption took locals by surprise, and could be explained by it producing pyroclastic flows, sudden emissions of gas and rock fragments, rather than lava, said volcanologist David Rothery of Britain's Open University.
Recovery work was going slowly, officials said, given the nature of the terrain and the way the volcano released large amounts of boiling mud, rock and ash down the mountain.
Amid the destruction, there was one glimmer of hope: The rescue of a black-and-white dog found alive in a home where four people lay dead.
By afternoon a new column of smoke was rising from the mountain and Guatemala's disaster agency said volcanic material was descending its south side, prompting an evacuation order and the closure of a nearby national highway.
Authorities in Guatemala are evaluating whether it's safe to resume the search for survivors and the dead on the third day after a volcanic eruption devastated several small towns.
It said the eruption has affected a total of 1.7 million people.
Thousands of people are staying in shelters, which includes the Church's Escuintla Guatemala Stake Center.
The toxic flow from Sunday's eruption rushed through areas it had never reached before, surprising and trapping entire neighborhoods, and cutting off access and fresh water to others. This number is expected to rise as much of the area is still too hot for rescue crews to search for bodies.
Only some communities in Escuintla are under an evacuation order, but even in the more distant central Escuintla businesses have closed and people are leaving.
"Disaster relief agency chief Sergio Cabanas told reporters: "'We will continue until we find the last victim, though we do not know how many there are.
Only 23 of the bodies recovered so far have been identified. "They are taking away our opportunity to say goodbye". Within 24 hours of the first eruption over the weekend, Shriners says an emergency medical team from its Galveston hospital was sent to provide care in Guatemala, where they've been working for days.
Naomi Diaz of the Ciraiz Beauty Academy said they were moved to help because they saw people who had lost everything.
The institute said there was a moderate flow of unsafe volcanic material down the volcano, and warned of the possibility of a strong flow in some areas.