"clump up" is not correct in written English.
To use the related verb "clump," you could say: "The snow clumped together to form a solid base."
They don't clump up and get really heavy.
They're much less inclined to clump up (and stop working) than their natural counterparts.
"That's how I found out whole-wheat flour doesn't clump up in a white sauce," she said.
By selecting different polymer building blocks, it's possible to "tune" the material to clump up at any specific flow-rate, he says.
It's a homegrown version of biofilm — mobs of microorganisms that clump up and encase themselves in largish sugar molecules so they are fairly impenetrable.
Skillful ringing is like a steady stream of sand; poor ringing clumps up like wet earth.
Snow's blowing in over Giff, melting on his glasses, clumping up between his pants and bare leg.
With the little icons' habit of clumping up on each other, that click-and-move exercise is harder than it looks.
£7.99 for 10 bulbs, suttons.co.uk 'St Keverne' A perfect daffodil: tall, large-cupped, eye-catching and good at clumping up over the years.
"Jack Snipe" clumps up beautifully over the years in a sunny spot, and gives that fabulous effect of a whole bouquet of blooms growing from the earth.
