The burning bush was in the desert at the top of a cliff.
(Subjected therefore to wind storms and fine particles of sand flying around)
From Wikipedia's article on St Elmo's Fire:
"Physically, St. Elmo's fire is a bright blue or violet glow, appearing like fire in some circumstances, from tall, sharply pointed structures such as lightning rods, masts, spires and chimneys, and on aircraft wings. St. Elmo's fire can also appear on leaves, grass, and even at the tips of cattle horns.[3] Often accompanying the glow is a distinct hissing or buzzing sound."
Therefore, in my opinion, it is safe to assume the burning bush that burned without burning up was subject to the phenomena known as St. Elmo's Fire.
My second response would be DAMP soil, you don't need to be starting any brush fires...
I think the best soil for all crops is loamy soil
The best soil that wheat will grow in is loamy well-drained soil. This type of soil has equal parts clay soil particles, sand and silt.
Loam soil
sandy soil
Topsoil is generally best, however soil type and quality will depend largely on the types of crops you're raising. Soil PH is a big factor in determining which plants will do well in your climate and soil type.
bush dasies
I think the best soil for all crops is loamy soil
The best soil that wheat will grow in is loamy well-drained soil. This type of soil has equal parts clay soil particles, sand and silt.
Every plant has different soil needs; there isn't one type of soil that is the best for all plants.
FDXGFDDG
Loam soil
sandy soil
The best type of soil for growing these plants is sand and top soil mixed with a little vitamin d.
fertizlalied soil or good soil and dry soil
sandy soil
Loamy and well drained soil.
Clayey soil