Heavy rains caused by the tail-end of a cold front affecting Luzon triggered a rush of silted water near the foot of restive Mayon Volcano in Albay Saturday, just as authorities warned of possible lahar flow in the area. 

Phivolcs said the cascading muddy water was a "sediment laden stream flow" that carried sand and rocks. 

The agency had earlier warned residents near river channels around Mayon to evacuate due to the possibility of lahar flows amid continuous rains in the area. 

In an advisory issued Saturday morning, Phivolcs warned of "potential lahars and sediment-laden stream flows on all river channels draining the slopes of Mayon Volcano." 

It cited the areas of Buyuan, Miisi, Mabinit, Basud, San Vicente, Buang, Quirangay and Masarawag-Maninila in its warning. 

Alert Level 4, the second highest alert level, remains hoisted over Mayon as the volcano continued to spew lava and ash. 

• Babala ng Phivolcs: Posibilidad ng lahar flow sa paligid ng Bulkang Mayon, mataas

-- with a report from Jonathan Cellona, ABS-CBN News